Thesuppressionoftheleaderofthefileproducesnothingstriking。
Ifthethingisdonewithoutcreatingadisturbance，theprocessiondoesnotalteritswaysatall。Thesecondcaterpillar，promotedtocaptain，knowsthedutiesofhisrankoft-hand:heselectsandleads，orratherhehesitatesandgropes。
Thebreakingofthesilkribbonisnotveryimportanteither。Iremoveacaterpillarfromthemiddleofthefile。Withmyscissors，soasnottocauseacommotionintheranks，Icutthepieceofribbononwhichhestoodandclearawayeverythreadofit。Asaresultofthisbreach，theprocessionacquirestwomarchingleaders，eachindependentoftheother。
Itmaybethattheoneintherearjoinsthefileaheadofhim，fromwhichheisseparatedbybutaslenderinterval；inthatcase，thingsreturntotheiroriginalcondition。Morefrequently，thetwopartsdonotbecomereunited。Inthatcase，wehavetwodistinctprocessions，eachofwhichwanderswhereitpleasesanddivergesfromtheother。Nevertheless，bothwillbeabletoreturntothenestbydiscoveringsoonerorlater，inthecourseoftheirperegrinations，theribbonontheothersideofthebreak。
Thesetwoexperimentsareonlymoderatelyinteresting。
Ihavethoughtoutanother，onemorefertileinpossibilities。Iproposetomakethecaterpillarsdescribeaclosecircuit，aftertheribbonsrunningfromitandliabletobringaboutachangeofdirectionhavebeendestroyed。
Thelocomotiveenginepursuesitsinvariablecoursesolongasitisnotshuntedontoabranch-line。IftheProcessionariesfindthesilkenrailalwaysclearinfrontofthem，withnoswitchesanywhere，willtheycontinueonthesametrack，willtheypersistinfollowingaroadthatnevercomestoanend？Whatwehavetodoistoproducethiscircuit，whichisunknownunderordinaryconditions，byartificialmeans。
Thefirstideathatsuggestsitselfistoseizewiththeforcepsthesilkribbonatthebackofthetrain，tobenditwithoutshakingitandtobringtheendofitaheadofthefile。Ifthecaterpillarmarchinginthevanstepsuponit，thethingisdone:theotherswillfollowhimfaithfully。
Theoperationisverysimpleintheorybutverydifficultinpracticeandproducesnousefulresults。Theribbon，whichisextremelyslight，breaksundertheweightofthegrainsofsandthatsticktoitandareliftedwithit。Ifitdoesnotbreak，thecaterpillarsattheback，howeverdelicatelywemaygotowork，feeladisturbancewhichmakesthemcurluporevenletgo。
Thereisayetgreaterdifficulty:theleaderrefusestheribbonlaidbeforehim；thecutendmakeshimdistrustful。Failingtoseetheregular，uninterruptedroad，heslantsofftotherightorleft，heescapesatatangent。IfItrytointerfereandtobringhimbacktothepathofmychoosing，hepersistsinhisrefusal，shrivelsup，doesnotbudge；andsoonthewholeprocessionisinconfusion。Wewillnotinsist:themethodisapoorone，verywastefulofeffortforatbestaproblematicalsuccess。
Weoughttointerfereaslittleaspossibleandobtainanaturalclosedcircuit。Canitbedone？Yes。Itliesinourpower，withouttheleastmeddling，toseeaprocessionmarchalongaperfectcirculartrack。Iowethisresult，whichiseminentlydeservingofourattention，topurechance。
Ontheshelfwiththelayerofsandinwhichthenestsareplantedstandsomebigpalm-vasesmeasuringnearlyayardandahalfincircumferenceatthetop。ThecaterpillarsoftenscalethesidesandclimbuptothemouldingwhichformsacornicearoundtheopeningThisplacesuitsthemfortheirprocessions，perhapsbecauseoftheabsolutefirmnessofthesurface，wherethereisnofearoflandslides，asontheloose，sandysoilbelow，andalso，perhaps，becauseofthehorizontalposition，whichisfavorabletoreposeafterthefatigueoftheascent。Itprovidesmewithacirculartrackallready-made。Ihavenothingtodobutwaitforanoccasionpropitioustomyplans。Thisoccasionisnotlongincoming。
Onthe30thofJanuary，1896，alittlebeforetwelveo’clockintheday，Idiscoveranumeroustroopmakingtheirwayupandgraduallyreachingthepopularcornice。Slowly，insinglefile，thecaterpillarsclimbthegreatvase，mounttheledgeandadvanceinregularprocession，whileothersareconstantlyarrivingandcontinuingtheseries。Iwaitforthestringtocloseup，thatistosay，fortheleader，whokeepsfollowingthecircularmoulding，toreturntothepointfromwhichhestarted。Myobjectisachievedinaquarterofanhour。Theclosedcircuitisrealizedmagnificently，insomethingverynearlyapproachingacircle。
Thenextthingistogetridoftherestoftheascendingcolumn，whichwoulddisturbthefineorderoftheprocessionbyanexcessofnewcomers；
itisalsoimportantthatweshoulddoawaywithallthesilkenpaths，bothnewandold，thatcanputthecorniceintocommunicationwiththeground。Withathickhair-pencilIsweepawaythesurplusclimbers；withabigbrush，onethatleavesnosmellbehindit——forthismightafterwardsproveconfusing——Icarefullyrubdownthevaseandgetridofeverythreadwhichthecaterpillarshavelaidonthemarch。Whenthesepreparationsarefinished，acurioussightawaitsus。
Intheuninterruptedcircularprocessionthereisnolongeraleader。
Eachcaterpillarisprecededbyanotheronwhoseheelshefollows，guidedbythesilktrack，theworkofthewholeparty；heagainhasacompanionclosebehindhim，followinghiminthesameorderlyway。Andthisisrepeatedwithoutvariationthroughoutthelengthofthechain。Nonecommands，orrathernonemodifiesthetrailaccordingtohisfancy；allobey，trustingintheguidewhooughtnormallytoleadthemarchandwhoinrealityhasbeenabolishedbymytrickery。
Fromthefirstcircuitoftheedgeofthetubtherailofsilkhasbeenlaidinpositionandissoonturnedintoanarrowribbonbytheprocession，whichneverceasesdribblingitsthreadasitgoes。Therailissimplydoubledandhasnobranchesanywhere，formybrushhasdestroyedthemall。
Whatwillthecaterpillarsdoonthisdeceptive，closedpath？Willtheywalkendlesslyroundandrounduntiltheirstrengthgivesoutentirely？
TheoldschoolmenwerefondofquotingBuridan’sAss，[note2]thatfamousDonkeywho，whenplacedbetweentwobundlesofhay，starvedtodeathbecausehewasunabletodecideinfavourofeitherbybreakingtheequilibriumbetweentwoequalbutoppositeattractions。Theyslanderedtheworthyanimal。TheAss，whoisnomorefoolishthananyoneelse，wouldreplytothelogicalsnarebyfeastingoffbothbundles。Willmycaterpillarsshowalittleofhismotherwit？Willthey，aftermanyattempts，beabletobreaktheequilibriumoftheirclosedcircuit，whichkeepsthemonaroadwithoutaturning？Willtheymakeuptheirmindstoswervetothissideorthat，whichistheonlymethodofreachingtheirbundleofhay，thegreenbranchyonder，quitenear，nottwofeetoff？
IthoughtthattheywouldandIwaswrong。Isaidtomyself:
"Theprocessionwillgoonturningforsometime，foranhour，twohoursperhaps；thenthecaterpillarswillperceivetheirmistake。Theywillabandonthedeceptiveroadandmaketheirdescentsomewhereorother。"
Thattheyshouldremainupthere，hardpressedbyhungerandthelackofcover，whennothingpreventedthemfromgoingaway，seemedtomeinconceivableimbecility。Facts，however，forcedmetoaccepttheincredible。Letusdescribethemindetail。
Thecircularprocessionbegins，asIhavesaid，onthe30thofJanuary，aboutmidday，insplendidweather。Thecaterpillarsmarchatanevenpace，eachtouchingthesternoftheoneinfrontofhim。Theunbrokenchaineliminatestheleaderwithhischangesofdirectionandallfollowmechanically，asfaithfultotheircircleasarethehandsofawatch。Theheadlessfilehasnolibertyleft，nowill；ithasbecomemereclock-work。Andthiscontinuesforhoursandhours。Mysuccessgoesfarbeyondmywildestsuspicions。Istandamazedatit，orratherIamstupefied。
Meanwhile，themultipliedcircuitschangetheoriginalrailintoasuperbribbonatwelfthofaninchbroad。Icaneasilyseeitglitteringontheredgroundofthepot。Thedayisdrawingtoacloseandnoalterationhasyettakenplaceinthepositionofthetrail。Astrikingproofconfirmsthis。
Thetrajectoryisnotaplanecurve，butonewhich，atacertainpoint，deviatesandgoesdownalittlewaytothelowersurfaceofthecornice，returningtothetopsomeeightinchesfartherImarkedthesetwopointsofdeviationinpencilonthevaseattheoutset。Well，allthatafternoonand，moreconclusivestill，onthefollowingdays，righttotheendofthismaddance，Iseethestringofcaterpillarsdipundertheledgeatthefirstpointandcometothetopagainatthesecond。Oncethefirstthreadislaid，theroadtobepursuedispermanentlyestablished。
Iftheroaddoesnotvary，thespeeddoes。Imeasureninecentimetres[note3]aminuteastheaveragedistancecovered。Buttherearemoreorlesslengthyhalts；thepaceslackensattimes，especiallywhenthetemperaturefalls。Atteno’clockintheeveningthewalkislittlemorethanalazyswayingofthebody。Iforeseeanearlyhalt，inconsequenceofthecold，offatigueanddoubtlessalsoofhunger。
Grazing-timehasarrived。Thecaterpillarshavecomecrowdingfromallthenestsinthegreenhousetobrowseuponthepine-branchesplantedbymyselfbesidethesilkenpurses。Thoseinthegardendothesame，forthetemperatureismild。Theothers，linedupalongtheearthenwarecornice，wouldgladlytakepartinthefeast；theyareboundtohaveanappetiteafteratenhours’walk。Thebranchstandsgreenandtemptingnotahand’sbreadthaway。Toreachittheyneedbutgodown；andthepoorwretches，foolishslavesoftheirribbonthattheyare，cannotmakeuptheirmindstodoso。Ileavethefamishedonesathalf-pastten，persuadedthattheywilltakecounselwiththeirpillowandthatonthemorrowthingswillhaveresumedtheirordinarycourse。
Iwaswrong。IwasexpectingtoomuchofthemwhenIaccordedthemthatfaintgleamofintelligencewhichthetribulationsofadistressfulstomachought，onewouldthink，tohavearoused。Ivisitthematdawn。Theyarelinedupasonthedaybefore，butmotionlessWhentheairgrowsalittlewarmer，theyshakeofftheirtorpor，reviveandstartwalkingagain。Thecircularprocessionbeginsanew，likethatwhichIhavealreadyseen。Thereisnothingmoreandnothinglesstobenotedintheirmachine-likeobstinacy。
Thistimeitisabitternight。Acoldsnaphassupervened，wasindeedforetoldintheeveningbythegardencaterpillars，whorefusedtocomeoutdespiteappearanceswhichtomydullersensesseemedtopromiseacontinuationofthefineweather。Atdaybreaktherosemary-walksareallasparklewithrimeandforthesecondtimethisyearthereisasharpfrost。Thelargepondinthegardenisfrozenover。Whatcanthecaterpillarsintheconservatorybedoing？Letusgoandsee。
Allareensconcedintheirnests，exceptthestubbornprocessionistsontheedgeofthevase，who，deprivedofshelterastheyare，seemtohavespentaverybadnight。Ifindthemclusteredintwoheaps，withoutanyattemptatorder。Theyhavesufferedlessfromthecold，thushuddledtogether。
’Tisanillwindthatblowsnobodyanygood。Theseverityofthenighthascausedtheringtobreakintotwosegmentswhichwill，perhaps，affordachanceofsafety。Eachgroup，asitrevivesandresumesitswalk，willpresentlybeheadedbyaleaderwho，notbeingobligedtofollowacaterpillarinfrontofhim，willpossesssomelibertyofmovementandperhapsbeabletomaketheprocessionswervetooneside。Rememberthat，intheordinaryprocessions，thecaterpillarwalkingaheadactsasascout。Whiletheothers，ifnothingoccurstocreateexcitement，keeptotheirranks，heattendstohisdutiesasaleaderandiscontinuallyturninghisheadtothissideandthat，investigating，seeking，groping，makinghischoice。Andthingshappenashedecides:thebandfollowshimfaithfully。Rememberalsothat，evenonaroadwhichhasalreadybeentravelledandberibboned，theguidingcaterpillarcontinuestoexplore。
ThereisreasontobelievethattheProcessionarieswhohavelosttheirwayontheledgewillfindachanceofsafetyhere。Letuswatchthem。
Onrecoveringfromtheirtorpor，thetwogroupslineupbydegreesintotwodistinctfiles。Therearethereforetwoleaders，freetogowheretheyplease，independentofeachother。Willtheysucceedinleavingtheenchantedcircle？Atthesightoftheirlargeblackheadsswayinganxiouslyfromsidetoside，Iaminclinedtothinksoforamoment。ButIamsoonundeceived。
Astheranksfillout，thetwosectionsofthechainmeetandthecircleisreconstituted。Themomentaryleadersoncemorebecomesimplesubordinates；
andagainthecaterpillarsmarchroundandroundallday。
Forthesecondtimeinsuccession，thenight，whichisverycalmandmagnificentlystarry，bringsahardfrost。InthemorningtheProcessionariesonthetub，theonlyoneswhohavecampedoutunsheltered，aregatheredintoaheapwhichlargelyoverflowsbothsidesofthefatalribbon。Iampresentattheawakeningofthenumbedones。Thefirsttotaketheroadis，asluckwillhaveit，outsidethetrack。Hesitatinglyheventuresintounknownground。HereachesthetopoftherimanddescendsupontheothersideontheearthinthevaseHeisfollowedbysixothers，nomore。Perhapstherestofthetroop，whohavenotfullyrecoveredfromtheirnocturnaltorpor，aretolazytobestirthemselves。
Theresultofthisbriefdelayisareturntotheoldtrack。Thecaterpillarsembarkonthesilkentrailandthecircularmarchisresumed，thistimeintheformofaringwithagapinit。Thereisnoattempt，however，tostrikeanewcourseonthepartoftheguidewhomthisgaphasplacedatthehead。Achanceofsteppingoutsidethemagiccirclehaspresenteditselfatlast；andhedoesnotknowhowtoavailhimselfofit。
Asforthecaterpillarswhohavemadetheirwaytotheinsideofthevase，theirlotishardlyimproved。Theyclimbtothetopofthepalm，starvingandseekingforfood。Findingnothingtoeatthatsuitsthem，theyretracetheirstepsbyfollowingthethreadwhichtheyhaveleftontheway，climbtheledgeofthepot，striketheprocessionagainand，withoutfurtheranxiety，slipbackintotheranks。
Oncemoretheringiscomplete，oncemorethecircleturnsandturns。
Thenwhenwillthedeliverancecome？ThereisalegendthattellsofpoorsoulsdraggedalonginanendlessrounduntilthehellishcharmisbrokenbyadropofholywaterWhatdropwillgoodfortunesprinkleonmyProcessionariestodissolvetheircircleandbringthembacktothenest？Iseeonlytwomeansofconjuringthespellandobtainingareleasefromthecircuit。Thesetwomeansaretwopainfulordeals。Astrangelinkingofcauseandeffect:fromsorrowandwretchednessgoodistocome。
And，first，shrivellingastheresultofcold。Thecaterpillarsgathertogetherwithoutanyorder，heapthemselvessomeonthepath，some，morenumerousthese，outsideit。Amongthelattertheremaybe，soonerorlater，somerevolutionarywho，scorningthebeatentrack，willtraceoutanewroadandleadthetroopbackhome。Wehavejustseenaninstanceofit。
Sevenpenetratedtotheinteriorofthevaseandclimbedthepalm。True，itwasanattemptwithnoresult，butstillanattempt。Forcompletesuccess，allthatneedbedonewouldhavebeentotaketheoppositeslope。Anevenchanceisagreatthing。Anothertimeweshallbemoresuccessful。
Inthesecondplace，theexhaustionduetofatigueandhunger。Alameonestops，unabletogofarther。Infrontofthedefaultertheprocessionstillcontinuestowenditswayforashorttime。Therankscloseupandanemptyspaceappears。Oncomingtohimselfandresumingthemarch，thecaterpillarwhohascausedthebreachbecomesaleader，havingnothingbeforehim。Theleastdesireforemancipationisallthathewantstomakehimlaunchthebandintoanewpathwhichperhapswillbethesavingpath。
Inshort，whentheProcessionaries’trainisindifficulties，whatitneeds，unlikeours，istorunofftherails。Theside-trackingislefttothecapriceofaleaderwhoaloneiscapableofturningtotherightorleft；andthisleaderisabsolutelynon-existentsolongastheringremainsunbroken。Lastly，thebreakingofthecircle，theonestrokeofluck，istheresultofachaotichalt，causedprincipallybyexcessoffatigueorcold。
Theliberatingaccident，especiallythatoffatigue，occursfairlyoften。
Inthecourseofsameday，themovingcircumferenceiscutupseveraltimesintotwoorthreesections；butcontinuitysoonreturnsandnochangetakesplace。ThingsgoonjustthesameTheholdinnovatorwhoistosavethesituationhasnotyethadhisinspiration。
Thereisnothingnewonthefourthday，Afteranicynightlikethepreviousone；nothingtotellexceptthefollowingdetail。YesterdayI
didnotremovethetraceleftbythefewcaterpillarswhomadetheirwaytotheinsideofthevase。Thistrace，togetherwithajunctionconnectingitwiththecircularroad，isdiscoveredinthecourseofthemorning。
Halfthetrooptakesadvantageofittovisittheearthinthepotandclimbthepalm；theotherhalfremainsontheledgeandcontinuestowalkalongtheoldrail。Intheafternoonthebandofemigrantsrejoinstheothers，thecircuitiscompletedandthingsreturntotheiroriginalcondition。
Wecometothefifthday。Thenightfrostbecomesmoreintense，withouthoweverasyetreachingthegreenhouse。Itisfollowedbybrightsunshineinacalmandlimpidsky。Assoonasthesun’srayshavewarmedthepanesalittle，thecaterpillars，lyinginheaps，wakeupandresumetheirevolutionsontheledgeofthevase。Thistimethefineorderofthebeginningisdisturbedandacertaindisorderbecomesmanifest，apparentlyanomenofdeliverancenearathand。Thescouting-pathinsidethevase，whichwasupholsteredinsilkyesterdayandthedaybefore，isto-dayfollowedtoitsoriginontherimbyapartofthebandandisthenabandonedafterashortloop。Theothercaterpillarsfollowtheusualribbon。
Theresultofthisbifurcationistwoalmostequalfiles，walkingalongtheledgeinthesamedirection，atashortdistancefromeachother，sometimesmeeting，separatingfartheron，ineverycasewithsomelackoforder。
Wearinessincreasestheconfusion。Thecrippled，whorefusetogoon，aremany。Breachesincrease；filesaresplitupintosectionseachofwhichhasitsleader，whopokesthefrontofhisbodythiswayandthattoexploretheground。Everythingseemstopointtothedisintegrationwhichwillbringsafety。Myhopesareoncemoredisappointed。Beforethenightthesinglefileisreconstitutedandtheinvinciblegyrationresumed。
Heatcomes，justassuddenlyasthecolddidTo-day，the4thofFebruary，isabeautiful，mildday。ThegreenhouseisfulloflifeNumerousfestoonsofcaterpillars，issuingfromthenests，meanderalongthesandontheshelf。Abovethem，ateverymoment，theringontheledgeofthevasebreaksupandcomestogetheragain。ForthefirsttimeIseedaringleaderswho，drunkwithheat，standingonlyontheirhinderprolegsattheextremeedgeoftheearthenwarerim，flingthemselvesforwardintospace，twistingabout，soundingthedepths。Theendeavourisfrequentlyrepeated，whilethewholetroopstops。Thecaterpillars’headsgivesuddenjerks；theirbodieswriggle。
Oneofthepioneersdecidestotaketheplunge。Heslipsundertheledge。
Fourfollowhim。Theothers，stillconfidingintheperfidioussilkenpath，darenotcopyhimandcontinuetogoalongtheoldroad。
Theshortstringdetachedfromthegeneralchaingropesaboutagreatdeal，hesitateslongonthesideofthevase；itgoeshalf-waydown，thenclimbsupagainslantwise，rejoinsandtakesitsplaceintheprocession。
Thistimetheattempthasfailed，thoughatthefootofthevase，notnineinchesaway，therelayabunchofpine-needleswhichIhadplacedtherewiththeobjectofenticingthehungryones。Smellandsighttoldthemnothing。Nearastheyweretothegoal，theywentupagain。
Nomatter，theendeavourhasitsuses。Threadswerelaidonthewayandwillserveasaluretofurtherenterprise。Theroadofdeliverancehasitsfirstlandmarks。Andtwodayslater，ontheeighthdayoftheexperiment，thecaterpillars——nowsingly，anoninsmallgroups，thenagaininstringsofsomelength——comedownfromtheledgebyfollowingthestaked-outpath。
Atsunsetthelastofthelaggardsisbackinthenest。
Nowforalittlearithmetic。Forseventimestwenty-fourhoursthecaterpillarshaveremainedontheledgeofthevase。Tomakeanampleallowanceforstopsduetothewearinessofthisoneorthatandaboveallfortheresttakenduringthecolderhoursofthenight，wewilldeductone-halfofthetime。Thisleaveseighty-fourhours’walking。Theaveragepaceisninecentimetres[note4]aminute。
Theaggregatedistancecovered，therefore，is453metres，agooddealmorethanaquarterofamile，whichisagreatwalkfortheselittlecrawlers。
Thecircumferenceofthevase，theperimeterofthetrack，isexactly1
m。35。[note5]Thereforethecirclecovered，alwaysinthesamedirectionandalwayswithoutresult，wasdescribedthreehundredandthirty-fivetimesThesefiguressurpriseme，thoughIamalreadyfamiliarwiththeabysmalstupidityofinsectsasaclasswhenevertheleastaccidentoccurs。IfeelinclinedtoaskmyselfwhethertheProcessionarieswerenotkeptuptheresolongbythedifficultiesanddangersofthedescentratherthanbythelackofanygleamofintelligenceintheirbenightedminds。Thefacts，however，replythatthedescentisaseasyastheascent。
Thecaterpillarhasaverysuppleback，welladaptedfortwistingroundprojectionsorslippingunderneath。Hecanwalkwiththesameeaseverticallyorhorizontally，withhisbackdownorup。Besides，henevermovesforwarduntilhehasfixedhisthreadtothegroundWiththissupporttohisfeet，hehasnofallstofear，nomatterwhathisposition。
Ihadaproofofthisbeforemyeyesduringawholeweek。AsIhavealreadysaid，thetrack，insteadofkeepingononelevel，bendstwice，dipsatacertainpointundertheledgeofthevaseandreappearsatthetopalittlefartheron。Atonepartofthecircuit，therefore，theprocessionwalksonthelowersurfaceoftherim；andthisinvertedpositionimpliessolittlediscomfortordangerthatitisrenewedateachturnforallthecaterpillarsfromfirsttolast。
Itisoutofthequestionthentosuggestthedreadofafalsestepontheedgeoftherimwhichissonimblyturnedateachpointofinflexion。
Thecaterpillarsindistress，starved，shelterless，chilledwithcoldatnight，clingobstinatelytothesilkribboncoveredhundredsoftimes，becausetheylacktherudimentaryglimmersofreasonwhichwouldadvicethemtoabandonit。
Experienceandreflectionarenotintheirprovince。Theordealofafivehundredyards’marchandthreetofourhundredturnsteachthemnothing；
andittakescasualcircumstancestobringthembacktothenest。Theywouldperishontheirinsidiousribbonifthedisorderofthenocturnalencampmentsandthehaltsduetofatiguedidnotcastafewthreadsoutsidethecircularpath。Somethreeorfourmovealongthesetrails，laidwithoutanobject，strayalittlewayand，thankstotheirwanderings，preparethedescent，whichisatlastaccomplishedinshortstringsfavouredbychance。
Theschoolmosthighlyhonouredto-dayisveryanxioustofindtheoriginofreasoninthedregsoftheanimalkingdom。LetmecallitsattentiontothePineProcessionary。
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[note1]:BookIV。，chap。viii——Translator’sNote。
[note2]:JeanBuridancirca1300-circa1360，afamousscholasticdoctor，whowasseveraltimesrectoroftheuniversityofParisandsubsequentlyfoundedtheuniversityofVienna。Heformsthesubjectofmanylegends，includingthatoftheargumentknownbyhisname，ofwhichnotraceistobefoundinanyofhisworks——Translator’sNote。
[note3]:31/2inches——Translator’sNote。
[note4]:31/2inches——Translator’sNote。
[note5]:4feet5inches——Translator’sNote。4，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916IV:THEPINEPROCESSIONARY:
METEOROLOGY
INJANUARYasecondmoultoccurs，leavingthecaterpillarlessfairtotheeye，whileatthesametimeendowinghimwithsomeverypeculiarorgans。Whenthemomenthascometoshedtheirskins，theProcessionariesclusterhiggledy-piggledyonthedomeofthenestandthere，iftheweatherbemild，remainmotionlessdayandnight。Itwouldseemasthoughthefactoftheircontact，oftheirmutualdiscomfort，whilethusheapedtogether，furnishesaresistance，afulcrum，whichfavourstheprocessofexcoriation。
Afterthissecondmoult，thehairsonthemiddleofthebackareofadullreddishcolour，whichismadepalerstillbytheinterpositionofnumerouslongwhitehairs。ButthisfadedcostumeisaccompaniedbythesingularorganswhichattractedtheattentionofRé；aumur，whowasgreatlyperplexedastotheirfunction。Intheplaceoriginallyoccupiedbythescarletmosaic，eightsegmentsofthecaterpillararenowcleftbyabroadtransversalgash，asortofthick-lippedmouth，whichopensandgapeswideatthecaterpillar’swill，orcloseswithoutleavingavisibletrace。
Fromeachoftheseexpandingmouthsrisesatumourwithafine，colourlessskin，asthoughthecreaturewereexposingitstenderinsideandinflatingit，fortheappearanceisalmostthatwhichwouldbepresentedbythevisceraprotrudingthroughskinincisedbythescalpel。Twolargedark-browndotsoccupythefrontfaceoftheprotuberance。Atthebackaretwoshort，flattuftsofrussetbristles，whichinthesunlightshinewitharichbrilliancy。
Allaroundisaradiatingborderoflongwhitehairs，spreadalmostflat。
Thisprotuberanceisextremelysensitive。Attheslightestirritationitgoesinagainanddisappearsunderthedarkintegument。Initsplaceopensanovalcrater，asortofhugestoma，whichswiftlybringsitslipstogether，closesandentirelydisappears。Thelongwhitehairsthatformamoustacheandimperialaroundthismouthfollowthemovementsofthecontractinglips。Afterfirstradiatingfromacentreandlyingflat，thesehairsriselikelevelledwheatwhichthewindhascaughtfrombeneathandmeettoformatransversalcrest，perpendiculartothecreature’sback。
Thishairyerectionproducesasuddenmodificationinthecaterpillar’saspect。Theredshinybristleshavedisappeared，buriedunderthedarkskin；thewhitehairs，nowstandingonend，formahirsutemane；anashytingehascreptintothegeneralcolourofthecostume。
Whencalmisrestored，assoonhappens，theslitsopenandyawnafresh；
thesensitiveprotuberancesemerge，quicktodisappearoncemoreshouldanycauseforalarmoccur。Thesealternateexpansionsandcontractionsarerapidlyrepeated。Iprovokethematwillinvariousways。Aslightpuffoftobacco-smokeimmediatelycausesthestomatatoyawnandtheprotuberancestoemerge。Onewouldthinkthattheinsectwasputtingitselfonitsguardanddisplayingsomespecialapparatusofinformation。Beforelongtheprotuberancesgoinagain。Asecondpuffofsmokebringsthemoutoncemore。But，ifthesmokeistooabundant，tooacrid，thecaterpillarwrigglesandwritheswithoutopeninghisapparatus。
OrelseItouchoneorotheroftheseuncoveredprotuberances，verydelicately，withabitofstraw。Thepimpleaffectedimmediatelycontracts，drawsintoitself，likethehornsoftheSnail，andisreplacedbyagapingmouth，whichinitsturncloses。Usually，butnotalways，thesegmentexcitedbythecontactofmystrawisimitatedbytheothers，bothfrontandback，whichclosetheirapparatusonebyone。
Whenundisturbedandinrepose，thecaterpillargenerallyhashisdorsalslitsexpanded；inmoving，hesometimesopensandsometimesclosesthem。
Ineithercaseexpansionandcontractionarefrequentlyrepeated。Constantlycomingtogetherandretreatingundertheskin，thelipsofthemouth-likeopeningthereforeendbylosingtheirbrittlemoustachesofrussethairs，whichbreakoff。Inthiswayasortofdustcollectsatthebottomofthecrater，adustformedofbrokenhairs，which，thankstotheirbarbs，sooncollectintolittletufts。Whentheslitexpandsrathersuddenly，thecentralprojectionshootsoutontheinsect’ssidesitsloadofhairyremnants，whichtheleastbreathblowsintoacloudofgoldenatomshighlydisagreeabletotheobserver。Ishallhavesomethingtosaypresentlyoftheitchtowhichheisatsuchtimesexposed。
Arethesepeculiarstomatadesignedmerelytocollecttheadjoiningbristlesandtogrindthemtopowder？Arethesefine-skinnedpapillæ；，whichinflateandascendfromthedepthsoftheirhiding-place，intendedtogetridoftheaccumulationofbrokenhairs？Orisitthesolefunctionofthispeculiarapparatustoprepare，attheexpenseofthecaterpillar’sfleece，anirritantdustwhichshallactasameansofdefence？Nothingtellsusso。
Certainlythecaterpillarisnotarmedagainsttheenquirerwhofromtimetotimetakesitintohisheadtocomeandexaminehimthroughamagnifying-glass。
Itisevenverydoubtfulwhetherhetroublesatallaboutthosepassionatecaterpillar-lovers，Calosoinasycophanta[note1]amonginsectsandtheCuckooamongbirds。Thosewhoconsumesuchfarehaveastomachexpresslyfashionedforthepurpose，astomachthatlaughsatblisteringhairsandpossiblyfindsanappetizingstimulantintheirsting。No，IdonotseethemotivesthatpromptedtheProcessionarytocleavehisbackwithsomanyslits，ifhemerelystripshimselfofhishairtothrowanirritatingdustinoureyes。Theremustcertainlybesomethingelseinquestion。
Ré；aumurmentionstheseopenings，ofwhichhemadeabriefstudy。
Hecallsthemstigmataandisinclinedtotakethemforexceptionalbreathing-holes。
Thattheyarenot，mymaster；noinsectcontrivesair-holesonitsback！
Moreover，themagnifying-glassrevealsnochannelofcommunicationwiththeinterior。Respirationplaysnoparthere；thesolutionoftheenigmamustlieelsewhere。
Theprotuberancesthatrisefromthoseexpandedcavitiesareformedofasoft，pale，hairlessmembrane，whichgivestheimpressionofavisceralhernia，asthoughthecaterpillarwerewoundedandexposingitsdelicateentrailstotheair。Thesensitivenessjusthereisgreat。Thelightesttouchwiththepointofahair-pencilcausestheimmediatein-drawingoftheprotuberancesandtheclosingofthecontaininglips。
Thetouchofasolidobjectevenisnotessential。Ipickupatinydropofwateronthepointofapinand，withoutshakingitoff，presentthisdroptothesensitiveprojection。Atthemomentwhencontactoccurstheapparatuscontractsandclosesup。TherecoiloftheSnail’shorns，withdrawingthevisualandolfactoryorgansintotheirsheaths，isnoprompter。
Everythingseemstoprovethattheseoptionaltumours，appearinganddisappearingatthecaterpillar’swill，areinstrumentsorsensorialperception。
Thecaterpillarexposesthemtoobtaininformation；hesheltersthemunderhisskintopreservetheirdelicatefunctions。Nowwhatisitthattheyperceive？Thisisadifficultquestion，inwhichthehabitsoftheProcessionaryalonecanaffordusalittleguidance。
Duringthewholewinter，thePineCaterpillarsareactiveonlyatnight。
Inthedaytime，whentheweatherisfine，theyreadilyrepairtothedomeofthenestandthereremainmotionless，gatheredintoheaps。Itisthehouroftheopen-airsiesta，underthepaleDecemberandJanuarysun。Asyetnoneleavesthehome。Itisquitelateintheevening，towardsnineo’clock，whentheysetout，marchinginanirregularprocession，tobrowseontheleavesofthebrancheshardby。Theirgrazingisaprotractedaffair。
Theflockreturnslate，sometimeaftermidnight，whenthetemperaturefallstoolow。
Secondly，itisintheheartofwinter，duringtheroughestmonths，thattheProcessionarydisplayshisfullactivity。Indefatigablyatthistimeofyearhespins，addingeachnightanewwebtohissilkentent；
atthistime，whenevertheweatherpermits，heventuresabroadontheneighbouringboughstofeed，togrowandtorenewhisskeinofsilk。
Byaveryremarkableexception，theharshseasonmarkedbyinactivityandlethargicreposeinotherinsectsisforhimtheseasonofbustleandlabour，oncondition，ofcourse，thattheinclemenciesoftheweatherdonotexceedcertainlimits。Ifthenorthwindblowtooviolently，sothatitisliketosweeptheflockaway；ifthecoldbetoopiercing，sothatthereisariskoffreezingtodeath；ifitsnow，orrain，orifthemistthickenintoanicydrizzle，thecaterpillarsprudentlystayathome，shelteringundertheirweatherprooftent。
Itwouldbeconvenienttosomeextenttoforeseetheseinclemencies。
Thecaterpillardreadsthem。Adropofrainsetshiminaflutter；asnowflakeexasperateshim。Tostartforthegrazing-groundsatdarkofnight，inuncertainweather，wouldbedangerous，fortheprocessiongoessomedistanceandtravelsslowly。Theflockwouldfareillbeforeregainingshelterdidanysuddenatmospherictroublesupervene，aneventofsomefrequencyinthebadseasonoftheyear。Sothathemaybeinformedinthisparticularduringhisnocturnalwinterrambles，canthePineCaterpillarbeendowedwithsomesortofmeteorologicalaptitudes？Letusdescribehowthesuspicionoccurredtome。
DivulgedIknownothow，myrearingofcaterpillarsunderglassacquiredacertainrenown。Itwastalkedaboutinthevillage。Theforest-ranger，aswornenemytodestructiveinsects，wantedtoseethegrazingofthefamouscaterpillars，ofwhomhehadretainedatoopoignantmemoryeversincethedaywhenhegatheredanddestroyedtheirnestsinapine-woodunderhischarge。Itwasarrangedthatheshouldcallthesameevening。
Hearrivesattheappointedhour，accompaniedbyafriend。Foramomentwesitandchatinfrontofthefire；then，whentheclockstrikesnine，thelanternislitandweallthreeenterthegreenhouse。
Thevisitorsareeagerforthespectacleofwhichtheyhaveheardsuchwonderfulthings，whileIamcertainofsatisfyingtheircuriosity。
But，but……whatisthis？Notacaterpillaronthenests，notoneonthefreshrationofbranches！Lastnightandonthepreviousnightstheycameoutincountlessnumbers；to-nightnotonerevealshimself。Canitbethattheyaremerelylateingoingtodinner？Cantheirhabitualpunctualitybeatfaultbecauseappetitehasnotyetarrived？Wemustbepatient……Teno’clock。Nothing。Eleven。Stillnothing。Midnightwasathandwhenweabandonedourwatch，convincedthatitwouldbevaintoprolongthesitting。YoucanimaginewhatanabjectfoolIlookedathavingthustosendmyguestsaway。
NextdayIthoughtthatIdimlyperceivedtheexplanationofthisdisappointment。
Itrainedinthenightandagaininthemorning。Snow，nottheearliestoftheyear，butsofarthemostabundant，whitenedthebrowoftheVentoux。[note2]Hadthecaterpillars，moresensitivethananyofustoatmosphericchanges，refusedtoventureforthbecausetheyanticipatedwhatwasabouttohappen？Hadtheyforeseentherainandthesnow，whichnothingseemedtoannounce，atalleventstous？Afterall，whynot？Letuscontinuetoobservethemandweshallseewhetherthecoincidenceisfortuitousornot。
Onthismemorableday，therefore，the13thofDecember，1895，Iinstitutethecaterpillars’meteorologicalobservatory。Ihaveatmydisposalabsolutelynoneoftheapparatusdeartoscience，notevenamodestthermometer，formyunluckystarcontinuesintheascendant，provingasunkindto-dayaswhenIlearntchemistrywithpipe-bowlsforcruciblesandbottlesthatoncecontainedsweetsforretorts。IconfinemyselftovisitingnightlytheProcessionariesinthegreenhouseandthoseinthegarden。Itisahardtask，especiallyasIhavetogotothefarendoftheenclosure，ofteninweatherwhenonewouldnotturnaDogoutofdoors。Isetdowntheactsofthecaterpillars，whethertheycomeoutorstayathome；I
notethestateoftheskyduringthedayandatthemomentofmyeveningexamination。
TothislistIaddthemeteorologicalchartofEuropewhichtheTempspublishesdaily。IfIwantmoreprecisedata，IrequesttheNormalSchoolatAvignontosendme，onoccasionsofviolentdisturbances，thebarometricalrecordsofitsobservatory。Thesearetheonlydocumentsatmydisposal。
Beforewecometotheresultsobtained，letmeoncemorerepeatthatmycaterpillars’meteorologicalinstitutehastwostations:oneinthegreenhouseandoneintheopenair，onthepinesintheenclosure。Thefirst，protectedagainstthewindandrain，isthatwhichIprefer:itprovidesmoreregularandmorecontinuousinformation。Infact，theopen-aircaterpillarsoftenenoughrefusetocomeout，eventhoughthegeneralconditionsbefavourable。Itisenoughtokeepthemathomeiftherebetoostrongawindshakingtheboughs，orevenalittlemoisturedrippingonthewebofthenests。Savedfromthesetwoperils，thegreenhousecaterpillarshaveonlytoconsideratmosphericincidentsofahigherorder。Thesmallvariationsescapethem；thegreatalonemakeanimpressiononthem:amostusefulpointfortheobserverandgoingalongwaytowardssolvingtheproblemforhim。Thecoloniesunderglass，therefore，providemostofthematerialformynotes；thecoloniesintheopenairaddtheirtestimony，whichisnotalwaysquiteclear。
Nowwhatdidtheytellme，thosegreenhousecaterpillarswho，onthe13thofDecember，refusedtoshowthemselvestomyguest，theforest-ranger？
Therainthatwastofallthatnightcouldhardlyhavealarmedthem:theyweresowellsheltered。ThesnowabouttowhitenMontVentouxwasnothingtothem:itwassofaraway。Moreover，itwasneithersnowingyetnorraining。
Someextraordinaryatmosphericevent，profoundandofvastextent，musthavebeenoccurring。ThechartsintheTempsandthebulletinoftheNormalSchooltoldmeasmuch。
Acyclonicdisturbance，comingfromtheBritishIsles，waspassingoverourdistrict；anatmosphericdepressionthelikeofwhichtheseasonhadnotasyetknown，hadspreadinourdirection，reachingusonthe13thandpersisting，inamoreorlessaccentuatedform，untilthe22nd。AtAvignonthebarometersuddenlyfellhalfaninch，to29。1in。，onthe13thandlowerstill，to29in。，onthe19th。
Duringthisperiodoftendays，thegardencaterpillarsmadenosortieonthepine-trees。True，theweatherwaschangeable。Therewereafewshowersoffinerainandsomeviolentgustsofthemistral；butmorefrequentlythereweredaysandnightswhentheskywassuperbandthetemperaturemoderate。Theprudentanchoriteswouldnotallowthemselvestobecaught。
Thelowpressurepersisted，menacingthem；andsotheystoppedathome。
Inthegreenhousethingshappenratherdifferently。Sortiestakeplace，butthestaying-indaysarestillmorenumerous。Itlooksasthoughthecaterpillars，alarmedatfirstbytheunexpectedthingshappeningoverhead，hadreassuredthemselvesandresumedwork，feelingnothing，intheirshelter，ofwhattheywouldhavesufferedoutofdoors——rain，snowandfuriousmistralblasts——andhadthensuspendedtheirworkagainwhenthethreatsofbadweatherincreased。
Thereis，indeed，afairlyaccurateagreementbetweentheoscillationsofthebarometerandthedecisionsoftheherd。Whenthecolumnofmercuryrisesalittle，theycomeout；whenitfallstheyremainathome。Thusonthe19th，thenightofthelowestpressure，29in。，notacaterpillarventuresoutside。
Asthewindandraincanhavenoeffectonmycoloniesunderglass，oneisledtosupposethatatmosphericpressure，withitsphysiologicalresults，sodifficulttodefine，isheretheprincipalfactor。Asforthetemperature，withinmoderatelimitsthereisnoneedtodiscussit。TheProcessionarieshavearobustconstitution，asbehovesspinnerswhoworkintheopenairinmidwinter。Howeverpiercingthecold，solongasitdoesnotfreeze，whenthehourcomesforworkingorfeedingtheyspinonthesurfaceofthenestorbrowseontheneighbouringbranches。
Anotherexample。AccordingtothemeteorologicalchartintheTemps，adepressionwhosecentreisneartheIlesSanguinaires，attheentranceoftheGulfofAjaccio，reachesmyneighbourhood，withaminimumof29。2
in。，onthe9thofJanuary。Atempestuouswindgetsup。Forthefirsttimethisyearthereisarespectablefrost。Theiceonthelargepondinthegardenistwoorthreeinchesthick。Thiswildweatherlastsforfivedays。
Ofcourse，thegardencaterpillarsdonotsallyforthonthepine-treeswhilethesearebatteredbysuchagale。
Theremarkablepartofthebusinessisthatthegreenhousecaterpillarsdonotventureoutoftheirnestseither。Andyetforthemtherearenoboughsdangerouslyshaken，nocoldpiercingbeyondendurance，foritisnotfreezingundertheglass。Whatkeepsthemincanbeonlythepassageofthatwaveofdepression。Onthe15ththestormceases；andthebarometerremainsbetween29。6and30in。fortherestofthemonthandagoodpartofFebruary。Duringthislongperiodtherearemagnificentsortieseveryevening，especiallyinthegreenhouse。
Onthe23rdand24thofFebruary，suddenlytheProcessionariesstopathomeagain，fornoapparentreason。Ofthesixnestsundercover，onlytwohaveafewrarecaterpillarsoutonthepine-branches，whilepreviously，inthecaseofallsix，Iusedeverynighttoseetheleavesbendingundertheweightofaninnumerablemultitude。Warnedbythisforecast，Ienterinmynotes:
"Somedeepdepressionisabouttoreachus。"
AndIhaveguessedright。Twodayslater，sureenough，themeteorologicalrecordoftheTempsgivesmethefollowinginformation:aminimumof29。2in。，comingfromtheBayofBiscayonthe22nd，reachesAlgeriaonthe23rdandspreadsovertheProvencecoastonthe24th。Thereisaheavysnow-fallatMarseillesonthe25th。
"Theships，"Ireadinmypaper，"presentacuriousspectacle，withtheiryardsandriggingwhite。ThatishowthepeopleofMarseilles，littleusedtosuchsights，pictureSpitzbergenandtheNorthPole。"
Herecertainlyisthegalewhichmycaterpillarsforesawwhentheyrefusedtogooutlastnightandthenightbefore；hereisthecentreofdisturbancewhichrevealeditselfatSé；rignanbyaviolentandicynorthwindonthe25thandthefollowingdays。AgainIperceivethatthegreenhousecaterpillarsarealarmedonlyattheapproachofthewaveofatmosphericdisturbance。Oncethefirstuneasinesscausedbythedepressionhadabated，theycameoutagain，onthe25thandthefollowingdays，inthemidstofthegale。asthoughnothingextraordinarywerehappening。
FromthesumofmyobservationsitappearsthatthePineProcessionaryiseminentlysensitivetoatmosphericvicissitudes，anexcellentquality，havingregardtohiswayoflifeinthesharpwinternights。Heforeseesthestormwhichwouldimperilhisexcursions。
Hiscapacityforscentingbadweatherverysoonwontheconfidenceofthehousehold。WhenwehadtogointoOrangetorenewourprovisions，itbecametheruletoconsulthimthenightbefore；and，accordingtohisverdict，wewentorstayedathome。Hisoracleneverdeceivedus。Inthesameway，simplefolkthatwewere，weusedintheolddaystointerrogatetheDor-beetle，[note3]anotherdoughtynocturnalworker。But，alittledemoralizedbyimprisonmentinacageandapparentlydevoidofanyspecialsensitiveapparatus，performinghisevolutions，moreover，inthemildautumnevenings，thecelebratedDung-beetlecouldneverrivalthePineCaterpillar，whoisactiveduringtheroughestseasonoftheyearandendowed，aseverythingwouldseemtoaffirm，withorgansquicktoperceivethegreatatmosphericfluctuations。
Ruralloreaboundsinmeteorologicalforecastsderivedfromanimals。
TheCat，sittinginfrontofthefireandwashingbehindherearswithasaliva-smearedpaw，foretellsanothercoldsnap；theCock，crowingatunusualhours，announcesthereturnoffineweather；theGuinea-fowl，withherscreeching，asofascytheonthegrindstone，pointstorain；theHen，standingononeleg，herplumageruffled，herheadsunkonherneck，feelsahardfrostcoming；theprettygreenTree-froginflateshisthroatlikeabladderattheapproachofastormand，accordingtotheProvenç；alpeasant，says:
"Ploù；ra，ploù；ra；itwillrain，itwillrain！。"
Thisrusticmeteorology，theheritageofthecenturies，doesnotshowupsobadlybesideourscientificmeteorology。
Arenotweourselveslivingbarometers？Everyveterancomplainsofhisgloriousscarswhentheweatherisabouttobreak。Oneman，thoughunwounded，suffersfrominsomniaorfrombaddreams；another，thoughabrain-worker，cannotdraganideaoutofhisimpotenthead。Eachofus，inhisownway，istriedbythepassageofthosehugefunnelswhichformintheatmosphereandhatchthestorm。
Couldtheinsect，withitsexceptionallydelicateorganization，escapethiskindofimpression？Itisunbelievable。Theinsect，ananyothercreature，shouldbeananimatedmeteorologicalinstrument，astruthfulinitsforecasts，ifweknewhowtoreadthem，asthelifelessinstrumentsofourobservatories，withtheirmercuryandtheircatgut。All，indifferentdegrees，possessageneralimpressionabilityanalogoustoourownandexercisedwithouttheaidofspecificorgans。Some，bettergiftedbecauseoftheirmodeoflife，mightwellbefurnishedwithspecialmeteorologicalapparatus。
ThePineProcessionaryseemstobelongtothisnumber。Inhissecondcostume，whenthesegmentsbearontheirdorsalfacesanelegantredmosaic，hediffersapparentlyfromothercaterpillarsonlybyamoredelicategeneralimpressionability，unlessthismosaicbeendowedwithaptitudesunknownelsewhere。Ifthenocturnalspinnerisstillnonetoogenerouslyequipped，itmustberememberedthattheseasonwhichhepassesinthisconditionisnearlyalwaysclement。ThereallyformidablenightshardlysetinbeforeJanuary。Butthen，asasafeguardinhisperegrinations，thePineProcessionarycleaveshisbackwithaseriesofmouthswhichyawnopentosampletheairfromtimetotimeandtogiveawarningofthesuddenstorm。
Untilfurtherevidenceisforthcoming，therefore，thedorsalslitsare，tomymind，meteorologicalinstruments，barometersinfluencedbythemainfluctuationsoftheatmosphere。Togobeyondsuspicions，thoughthesearewellbased，isformeimpossible。Ilacktheequipmentnecessarytodelvemoredeeplyintothesubject。ButIhavegivenahint。Itisforthosewhoarebetterfavouredinthematterofresourcestofindthefinalsolutionofthisinterestingproblem。
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[note1]:AlargecarnivorousBeetle——Translator’sNote。
[note2]:ThehighestmountainintheneighbourhoodofSé；rignanCf。TheHuntingWasps，byJ。HenriFabre，translatedbyAlexanderTeixeiradeMattos:chap。xi——Translator’sNote。
[note3]:Geotrupesstercorarius，alargeDung-beetle。Cf。TheLifeandLoveoftheInsect，byJ。HenriFabre，translatedbyAlexanderTeixeiradeMattos:chap。ix——Translator’sNote。5，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916V:THEPINEPROCESSIONARY:
THEMOTH
WHENMarchcomes，thecaterpillarsrearedindomesticityneverceaseprocessioning。Manyleavethegreenhouse，whichremainsopen；theygoinsearchofasuitablespotfortheapproachingmetamorphosis。Thisisthefinalexodus，thedefiniteabandonmentofthenestandthepine-tree。Thepilgrimsaremuchfaded，whitish，withafewrussethairsontheirbacks。
Onthe20thofMarchIspendawholemorningwatchingtheevolutionsofafilesomethreeyardsinlength，containingaboutahundredemigrants。
Theprocessiontoilsgrimlyalong，undulatingoverthedustyground，whereitleavesafurrow。Thenitbreaksintoasmallnumberofgroups，whichcrowdtogetherandremainquiescentsaveforsuddenoscillationsofthehind-quarters。Afterahaltofvaryingduration，thesegroupsresumetheirmarch，henceforwardformingindependentprocessions。
Theytakenosettleddirection。Thisonegoesforward，thatonegoesback；oneturnstotheleftandanothertotheright。
Thereisnoruleabouttheirmarching，nopositivegoal。Oneprocession，afterdescribingaloopretracesitssteps。Yetthereisageneraltendencytowardsthatwallofthegreenhousewhichfacesthesouthandreflectsthesun’srayswithaddedfervour。Thesoleguide，itwouldseem，istheamountofsunwhichaplaceobtains；thedirectionswhencethegreatestheatcomesarepreferred。
Afteracoupleofhoursofmarchingandcountermarching，thefragmentaryprocessions，comprisingeachascoreofcaterpillars，reachthefootofthewall。Herethesoilispowdery，verydry，easytoburrowin，althoughmadesomewhatfirmerbytuftsofgrass。Thecaterpillarattheheadoftherowexploreswithhismandibles，digsalittle，investigatesthenatureoftheground。Theothers，trustingtheirleader，followhimwithdocility，makingnoattemptsoftheirown。whatevertheforemostdecideswillbeadoptedbyall。Here，inthechoiceofamattersoimportantasthespotwhereatthetransformationshalltakeplace，thereisnoindividualinitiative。
Thereisonlyonewill，theleader’s。Thereisonlyonehead，sotospeak；theprocessionmaybecomparedwiththechainofsegmentsofanenormousworm。
Finallysomespotisrecognizedaspropitious。Theleadingcaterpillarhalts，pusheswithhishead，digswithhismandibles。Theothers，stillinacontinuousline，arriveonebyoneandlikewisecometoahalt。Thenthefilebreaksupintoaswarmingheap，inwhicheachofthecaterpillarsresumeshisliberty。Alltheirbacksarejogglingpell-mell；alltheirheadsareplungedintothedust；alltheirfeetareraking，alltheirmandiblesexcavatingthesoilThewormhaschoppeditselfintoagangofindependentworkers。
Anexcavationisformedinwhich，littlebylittle，thecaterpillarsburythemselves。Forsometimetocome，theunderminedsoilcracksandrisesandcoversitselfwithlittlemole-hills；thenallisstill。Thecaterpillarshavedescendedtoadepthofthreeinches。Thisisasfarastheroughnessofthesoilpermitsthemtogo。Inloosersoil，theexcavationwouldattainamuchgreaterdepth。Thegreenhouseshelf，suppliedwithfinesand，hasprovidedmewithcocoonsplacedatadepthoffromeighttotwelveinches。Iwouldnotassertthattheintermentmightnotbemadestilllowerdown。Forthemostpart，theburialiseffectedincommon，bymoreorlessnumerousclustersandatdepthswhichvarygreatly，accordingtothenatureofthesoil。
Afortnightlater，letusdigatthepointwherethedescentundergroundwasmade。Hereweshallfindthecocoonsassembledinbunches，cocoonsofsorryappearance，soiledastheyarewithearthyparticlesheldbysilkenthreads。Whenstrippedoftheirroughexterior，theyarenotwithoutacertainelegance。Theyarenarrowellipsoids，pointedatbothends，measuringtwenty-fivemillimetresinlengthandninemillimetres[note1]inthickness。Thesilkofwhichtheyarecomposedisveryfineandofadullwhite。Thefragilityofthewallsisremarkablewhenwehaveseentheenormousquantityofsilkexpendedontheconstructionofthenest。
Aprodigiousspinnerwherehiswinterhabitationisconcerned，thecaterpillarfindshisglandsexhaustedandisreducedtothestrictlynecessaryamountwhenthetimecomesformakingthecocoon。Toopoorinsilk，hestrengthenshisflimsycellwithafacingofearth。WithhimitisnottheindustryoftheBembex，[note2]whoinsertsgrainsofsandinhersilkywebandmakesasolidcasketofthewhole；itisasummarysortofart，devoidofdelicacy，whichjustcasuallystickstogetherthesurroundingearthyrefuse。
Moreover，ifcircumstancesdemandit，thePineCaterpillarcandowithoutearth。IntheverymidstofthenestIhavesometimes——veryrarely，itistrue——discoveredcocoonswhichwereperfectlyclean。Notascrapofalienmatterdefiledtheirfinewhitesilk。Ihaveobtainedsimilarspecimensbyplacingcaterpillarsunderabell-glassinapanprovidedonlywithafewpine-twigs。Betterstillanentireprocession，agood-sizedonetoo，gatheredattheopportunemomentandenclosedinalargeboxcontainingnosandnoranymaterialwhatever，spunitscocoonswithnoothersupportthanthebarewalls。Theseexceptions，provokedbycircumstancesinwhichthecaterpillarisnotfreetoactaccordingtohiswont，doesnotinanywayinvalidatetherule。Toprepareforthetransformation，theProcessionaryburieshimself，tothedepthofnineinchesandmore，ifthesoilpermit。
Hereacuriousproblemforcesitselfupontheobserver’smind。HowdoestheMothcontrivetoascendfromthecatacombsintowhichthecaterpillarhasdescended？Notinthefineryofherperfectstate——thebigwingswiththeirdelicatescales，thesweepingantenna-plumes——dareshebravetheasperitiesofthesoil，orshewouldissuethencealltattered，rumpledandunrecognizable。Andthisisnotthecase:farfromit。Moreover，whatmeanscansheemploy，shesofeeble，tobreakthecrustofearthintowhichtheoriginaldustwillhaveturnedaftertheslightestofshowers？
TheMothappearsattheendofJulyorinAugust。TheburialtookplaceinMarch。Rainmusthavefallenduringthislapseoftime，rainwhichbeatsdownthesoil，cementsitandleavesittohardenonceevaporationhassetin。NevercouldaMoth，unlessattiredandequippedwithtoolsforthepurpose，breakherwaythroughsuchanobstacle。Shewouldperforcerequireaboring-toolandacostumeofextremesimplicity。Guidedbytheseconsiderations，Iinstituteafewexperimentswhichwillgivemethekeytotheriddle。
InAprilImakeacopiouscollectionofcocoonsOftheseIplacetenortwelveatthebottomoftest-tubesofdifferentdiametersandlastofall，Ifilltheapparatuswithsandysoil，siftedandveryslightlymoistened。
Thecontentsarepresseddown，butinmoderation，forfearofinjuringthecocoonsbelow。WhenthemonthofAugustcomes，thecolumnofearth，dampattheoutset，hassetsofirmly，thankstoevaporation，that，whenIreversethetesttube，nothingtricklesout。Ontheotherhand，somecocoonshavebeenkeptnakedunderametalliccover。Thesewillteachmewhattheburiedcocoonswouldnotbeabletoshow。Theyfurnishme，infact，withrecordsofthegreatestinterest。Onissuingfromthecocoon，thePineBombyxhasherfinerybundledupandpresentstheappearanceofacylinderwithroundedends。Thewings，theprincipalobstacletoundergroundlabourarepressedagainstthebreastlikenarrowscarves；theantennæ；，anotherseriousembarrassment，havenotyetunfoldedtheirplumesandareturnedbackalongtheMoth’ssides。Thehair，whichlaterformsadensefleece，islaidflat，pointingbackwards。Thelegsalonearefree，fairlyactiveandendowedwithacertainvigour。Thankstothisarrangement，whichdoesawaywithallawkwardprojections，theascentthroughthesoilismadepossible。
True，everyMoth，atthemomentofquittinghershell，isthissortofswathedmummy；butthePineBombyxhasinadditionanexceptionalaptituderenderednecessarybythefactthatshehatchesundertheground。Whiletheothers，onceoutofthecocoon，hastentospreadtheirwingsandarepowerlesstodefertheirdevelopment，she，byvirtueofanindispensableprivilege，remainsinhercompactandwrapped-upconditionaslongascircumstancesdemandit。Undermybell-glassesIseesomewho，thoughbornuponthesurface，fortwenty-fourhoursdragthemselvesoverthesandorclingtothepine-branches，beforeuntyingtheirsashesandunfurlingthemaswings。
Thisdelayisevidentlyessential。Toascendfrombeneaththeearthandreachtheopenair，theMothhastoborealongtunnel，whichrequirestime。Shewilltakegoodcarenottospreadherfinerybeforeemerging，foritwouldhamperherandwoulditselfberumpledandbadlycreased。
Thereforethecylindricalmummypersistsuntilthedeliveranceiseffected；
and，iflibertyhappentobeacquiredbeforetheappointedmoment，thefinalevolutiondoesnottakeplaceuntilafteralapseoftimeinconformitywithusage。
Weareacquaintedwiththeequipmentforemergence，thetight-fittingjerkinindispensableinanarrowgallery。Now，whereistheboring-tool？
Thelegs，thoughfree，wouldherebeinsufficient:theywouldscrapetheearthlaterally，enlargingthediameteroftheshaft，butcouldnotprolongtheexitvertically，abovetheinsect’shead。Thistoolmustbeinfront。
PassthetipofyourfingerovertheMoth’sheadYouwillfeelafewveryroughwrinkles。Themagnifying-glassshowsusmoreWefind，betweentheeyesandhigherupfourorfivetransversalscales，sosetastooverlaponeanother；theyarehardandblackandaretrimmedcrescent-wiseattheendsThelongestandstrongestistheuppermost，whichisinthemiddleoftheforehead，Thereyouhavethecentre-bitofyourboring-tool。
Tomakeourtunnelsingraniticrockswetipourdrillswithdiamondpoints。ForasimilartasktheBombyx，alivingdrill，wearsimplantedonherforeheadarowofcrescents，hardanddurableassteel，aregulartwist-bit。Withoutsuspectingitsuse，Ré；aumurwasperfectlyawareofthismarvellousimplement，whichhecalledscalystairs:
"WhatdoesitprofitthisMoth，"heasks，"thatsheshouldthushavethefrontofherheadformedlikescalystairs？ThatisjustwhatIdonotknow。"
Mytest-tubes，learnedmaster，willtellus。Bygoodfortune，ofthenumerousMothsascendingfromthebottomofmyapparatusthroughacolumnofsandsolidifiedbytheevaporationoftheoriginalmoisture，somearemakingtheirwayupwardsagainstthesideofthetube，enablingmetofollowtheirmanoeuvres。Iseethemraisingtheircylindricalbodies，buttingwiththeirheads，jerkingnowinonedirection，nowinanotherThenatureoftheirtaskisobvious。Thecentre-bits，withanalternatingmovement，areboringintotheagglutinatedsand。Thepowderywreckagetricklesdownfromoverheadandisatoncethrustbackwardbythelegs。Alittlespaceformsatthetopofthevault；andtheMothmovessomuchnearertothesurface。Bythefollowingday，thewholecolumn，teninchesinheight，willbeperforatedwithastraight，perpendicularshaft。
Shallwenowformanideaofthetotalworkperformed？Letusturnthetest-tubeupsidedown。Thecontents，asIhavesaid，willnotfallout，fortheyhavesetintoablock；butfromthetunnelsboredbytheMothtricklesallthesandcrumbledbythecrescentsofthedrill。Theresultisacylindricalgallery，ofthewidthofalead-pencil，verycleanlycutandreachingtothebottomofthesolidmass。
Areyousatisfied，mymaster？Doyounowperceivethegreatutilityofthescalystairs？Wouldyounotsaythatwehavehereamagnificentexampleofaninstrumentsuperlativelyfittedforadefinitetask？Isharethisopinion，forIthink，withyou，thatasovereignReasonhasinallthingscoordinatedthemeansandtheend。
Butletmetellyou:wearecalledold-fashioned，youandI；withourconceptionofaworldruledbyanIntelligence，wearequiteoutoftheswim。Order，balance，harmony:thatisallsillynonsense。
Theuniverseisafortuitousarrangementinthechaosofthepossible。
Whatiswhitemightaseasilybeblack，whatisroundmightbeangular，whatisregularmightbeshapelessandharmonymightjustaswellbediscord。
Chancehasdecidedallthings。
Yes，weareapairofprejudicedoldfogeyswhenwelingerwithacertainfondnessoverthemarvelsofperfection。Whotroublesaboutthesefutilitiesnowadays？So-calledseriousscience，thesciencewhichspellshonour，profitandrenown，consistsinslicingyouranimalwithverycostlyinstrumentsintotinycircularsections。Myhousekeeperdoesasmuchwithabunchofcarrots，withnohigherpretentionthantoconcoctamodestdish，whichisnotaninvariablesuccess。Intheproblemoflifearewemoresuccessfulwhenwehavesplitafibreintofourandcutacellintoshavings？Ithardlyseemsso。Theriddleisasdarkasever。Ah，howmuchbetterisyourmethod，mydearmaster；aboveall，howmuchloftieryourphilosophy，howmuchmorewholesomeandinvigorating！
HereatlastistheMothatthesurface。Withthedeliberateslownessdemandedbysodelicateanoperation，shespreadsherbunchedwings，extendsherantennæ；andpuffsoutherfleece。Hercostumeisamodestone:
upperwingsgrey，stripedwithafewcrinklybrownstreaks；under-wingswhite；thoraxcoveredwiththickgreyfur；abdomencladinbright-russetvelvet。Thelastsegmenthasapale-goldsheen。Atfirstsightitappearsbare。Itisnot，however；but，inplaceofhairslikethoseoftheothersegments，ithas，onitsdorsalsurface，scalessowellassembledandsoclosetogetherthatthewholeseemstoformacontinuousblock，likeanugget。
Letustouchthistrinketwiththepointofaneedle。Howevergentlywerub，amultitudeofscalescomeoffandflutterattheleastbreath，shininglikemicaspangles。Theirconcaveform，theirshape，anelongatedoval，theircolouring，whiteinthelowerhalfbutreddishgoldintheupper，givethem，ifweallowforthedifferenceinsize，acertainresemblancetothescalessurroundingtheheadsofsomeofthecentaurytribe。Suchisthegoldenfleeceofwhichthemotherwilldespoilherselfinordertocoverthecylinderofhereggs。Thenuggetofherhind-quarters，exfoliatedspanglebyspangle，willformaroofforthegermsarrangedlikethegraininacorn-cob。
Iwasanxioustowatchtheactualplacingoftheseprettytiles，whicharefixedatthepaleendwithaspeckofcement，leavingthecolouredendfree。Circumstancesdidnotfavourme。Inactiveallday，motionlessonsomeneedleofthelowerbranches，theMoth，whoselifeisveryshort，movesonlyinthedarknessofthenight。Bothhermatingandegg-layingarenocturnal。Onthemorrow，allisfinished:theBombyxhaslived。Undertheseconditions，itwasimpossible，bythedoubtfulbeamsofalantern，tofollowsatisfactorilythelabourofthemotheronthepine-treesinthegarden。
Iwasnomorefortunatewiththecaptivesinmybell-glasses。Afewdidlaytheireggs，butalwaysataveryadvancedhourofthenight，anhourwhichfoundmyvigilanceatfault。Thelightofacandleandeyesheavywithsleepwereoflittleavailwhenitcametoanalysingthesubtleoperationsofthemotherassheputsherscalesinplace。Wewillsaynothingofthelittlethatwasimperfectlyseen。
Letusclosewithafewwordsofsylviculturalpractice。ThePineProcessionaryisavoraciouscaterpillarwho，whilerespectingtheterminalbud，protectedbyitsscalesanditsresinousvarnish，completelydenudestheboughandimperilsthetreebyleavingitbald。Thegreenpine-needles，thatmaneinwhichthevegetablevigourofthetreeresides，areshorntotheroots。
Howarewetoremedythis？
Whenconsultedonthesubject，theforest-rangerofmyparishtoldmethatthecustomistogofromtreetotreewithpruning-shearsfittedonalongpoleandtocutdownthenests，afterwardsburningthem。Themethodisatroublesomeone，forthesilkenpursesareoftenatconsiderableheights。
Moreover，itisnotwithoutdanger。Attackedbythehairydust，thedestroyerssoonexperienceintolerablediscomfort，atortureofirritationwhichmakesthemrefusetocontinuethework。Tomythinkingitwouldbebettertooperatebeforetheappearanceofthenests。
ThePineBombyxisaverybadflyer。Incapableofsoaring，almostliketheSilk-moth，shefluttersaboutandblunderstoearthagain；andherbesteffortsbarelysucceedinbringinghertothelowerbranches，whichalmostdragalongtheground。Herearedepositedthecylindersofeggs，ataheightofsixfeetatmost。Itistheyoungcaterpillarswho，fromoneprovisionalencampmenttoanother，graduallyascend，attaining，stagebystage，thesummitsuponwhichtheyweavetheirfinaldwellings。Oncewegraspthispeculiarity，therestisplainsailing。
InAugustweinspectthelowerfoliageofthetree:aneasyexamination，foritiscarriedonnohigherthanourheads。TowardsthefarendofthetwigsitiseasytoespytheBombyx’eggs，packedintocylindersthatresemblescalycatkins。Theirsizeandtheirwhitishcolourmakethemshowupamidthesombregreen。Gatheredwiththedoublepine-needlethatbearsthem，thesecylindersarecrushedunderfoot，asummaryfashionofstampingoutanevilbeforeitspreads。
ThisIhavedoneinthecaseofthefewpine-treesinmyenclosure。
Andthesamemightbedoneinthewiderforestexpansesandmoreespeciallyinparksandgardens，wheresymmetricalfoliationisoneofthegreatbeautiesofthetree。Iwilladdthatitiswisetopruneeveryboughthatdroopstoearthandtokeepthefootoftheconiferbaretoaheightofsixfeetorso。Intheabsenceoftheselowerstairs，theonlyonesthattheBombyxwithherclumsyflightcanreach，shewillnotbeabletopopulatethetree。
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[note1]:。975by。351inch——Translator’sNote。
[note2]:Cf。TheHuntingWasps:chaps。xivtoxvii——Translator’sNote。6，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916VI:THEPINEPROCESSIONARY:
THESTINGINGPOWER
THEPineProcessionaryhasthreecostumes:thatofinfancy，ascanty，raggedfleece，amixtureofblackandwhite；thatofmiddleage，therichestofthethree，whenthesegmentsdeckthemselvesontheirdorsalsurfacewithgoldentuftsandamosaicofbarepatches，scarletincolour；andthatofmaturity，whentheringsarecleftbyslitswhichonebyoneopenandclosetheirthicklips，champingandgrindingtheirbristlingrussetbeardsandchewingthemintolittlepellets，whicharethrownoutonthecreature’ssideswhenthebottomofthepocketswellsuplikeatumour。
Whenwearingthislastcostume，thecaterpillarisverydisagreeabletohandle，oreventoobserveatclosequarters。Ihappened，quiteunexpectedly，tolearnthismorethoroughlythanIwished。
Afterunsuspectinglypassingawholemorningwithmyinsects，stoopingoverthem，magnifying-glassinhand，toexaminetheworkingoftheirslits，Ifoundmyforeheadandeyelidssufferingwithrednessfortwenty-fourhoursandafflictedwithanitchingevenmorepainfulandpersistentthanthatproducedbystingofanettle。Onseeingmecometodinnerinthissadplight，withmyreddenedandswollenandmyfacerecognizable，thefamilyanxiouslyenquiredwhathadhappenedtomeandwerenotreassureduntilItoldthemofmymishap。
Iunhesitatinglyattributemypainfulexperiencetotheredhairsgroundtopowderandcollectedintoflakes。Mybreathsoughtthemoutintheopenpocketsandcarriedthemmyface，whichwasverynear。Theunthinkinginterventionofmyhands，whichnowandagainsoughttoeasethediscomfort，merelyaggravatedtheillbyspreadingtheirritatingdust。
No，thesearchfortruthonthebackoftheProcessionaryisnotallsunshine。Itwasonlyafteranight’srestthatIfoundmyselfprettywellrecovered，theincidenthavingnootherilleffects。Letuscontinue，however。Itiswelltosubstitutepremeditatedexperimentsforchancefacts。
Thelittlepocketsofwhichthedorsalslitsformtheentranceareencumbered，asIhavesaid，withhairyrefuse，eitherscatteredorgatheredintoflakes。
Withthepointofapaint-brushIcollect，whentheygapeopen，alittleoftheircontentsandrubitonmywristorontheinsideofmyfore-arm。
Ihavenotlongtowaitfortheresult。Soontheskinturnsredandiscoveredwithpalelenticularswellings，similartothoseproducedbyanettle-sting。Withoutbeingverysharp，thepainwasextremelyunpleasant。
Bythefollowingday，itching，rednessandlenticularswellingshadalldisappeared。Thisistheusualsequenceofevents；butletmenotomittosaythattheexperimentdoesnotalwayssucceed。Theefficacyofthefluffydustappearssubjecttogreatvariations。
TherehavebeenoccasionswhenIhaverubbedmyselfwiththewholecaterpillar，orwithhiscastskin，orwiththebrokenhairsgatheredonapaint-brush，withoutproducinganyunpleasantresults。TheirritantdustseemstovaryinqualityaccordingtocertaincircumstanceswhichIhavenotbeenabletodiscover。
Frommyvarioustestsitisevidentthatthediscomfortiscausedbythedelicatehairswhichthelipsofthedorsalmouths，gapingandclosingagain，neverceasegrinding，tothedetrimentoftheirbeardsandmoustaches。
Theedgesoftheseslits，astheirbristlesruboff，furnishthestingingdust。
Havingestablishedthisfact，letusproceedtomoreseriousexperiments。
InthemiddleofMarch，whentheProcessionariesforthemostparthavemigratedunderground，Idecidetoopenafewnests，asIwishtocollecttheirlastinhabitantsforthepurposeofmyinvestigations。Withouttakinganyprecautions，myfingerstugatthesilkendwelling，whichismadeofsolidstuff；theytearitintoshreds，searchitthroughandthrough，turnitinsideoutandbackagain。