OncemoreandthistimeinamoreseriousfashionIamthevictimofmyunthinkingenthusiasm。Hardlyistheoperationcompletedwhenthetipsofmyfingersbegintohurtingoodearnest，especiallyinthemoredelicatepartprotectedbytheedgeofthenail。Thefeelingislikethesharppainofasorethatisbeginningtofester。Alltherestofthedayandallthroughthenight，thepainpersists，troublesomeenoughtorobmeofmysleep。Itdoesnotquietdownuntilthefollowingday，aftertwenty-fourhoursofpettytorment。
　　Howdidthisnewmisadventurebefallme？Ihadnothandledthecaterpillars:
　　indeed，therewereveryfewoftheminthenestatthetime。Ihadcomeuponnoshedskins，forthemoultsdonottakeplaceinsidethesilkenpurse。Whenthemomenthascometodoffthesecondcostume，thatoftheredmosaic，thecaterpillarsclusteroutside，onthedomeoftheirdwelling，andthereleaveinasingleheaptheiroldclothesentangledwithbitsofsilk。Whatislefttoexplaintheunpleasantconsequencestowhichthehandlingofthenestexposesus？
　　Thebrokenredbristlesareleft，thefallenhairsformingadustthatisinvisiblewithoutaverycarefulexamination。ForalongtimetheProcessionariescrawlandswarmaboutthenest；theypasstoandfro，penetratingthethicknessofthewallwhentheygotothepasturesandwhentheyreturntotheirdormitory。Whethermotionlessoronthemove，theyareconstantlyopeningandclosingtheirapparatusofinformation，thedorsalmouths。Atthemomentofclosing，thelipsoftheseslits，rollingoneachotherlikethecylindersofaflattening-mill，catchholdofthefluffnearthem，tearitoutandbreakitintofragmentswhichthebottomofthepocket，presentlyreascending，shootsoutside。
　　Thusmyriadsofirritantparticlesaredisseminatedandsubtlyintroducedintoeverypartofthenest。TheshirtofNessusburnttheveinsofwhosoworeit；thesilkoftheProcessionary，anotherpoisonedfabric，setsonfirethefingersthathandleit。
　　Theloathsomehairslongretaintheirvirulence。Iwasoncesortingoutsomehandfulsofcocoons，manyofwhichwerediseased。Asthehardnessofthecontentswasusuallyanindicationthatsomethingwaswrong，Itoreopenthedoubtfulcocoonswithmyfingers，inordertosavethenon-contaminatedchrysalids。Mysortingwasrewardedwiththesamekindofpain，especiallyundertheedgesofthenails，asIhadalreadysufferedwhentearingthenests。
　　ThecauseoftheirritationonthisoccasionwassometimesthedryskindiscardedbytheProcessionaryonbecomingachrysalisandsometimestheshrivelledcaterpillarturnedintoasortofchalkycylinderthroughtheinvasionofthemalignantfungus。Sixmonthslater，thesewretchedcocoonswerestillcapableofproducingrednessandirritation。
　　Examinedunderthemicroscope，therussethairs，thecauseoftheitching，arestiffrods，verysharpateitherendandarmedwithbarbsalongtheupperhalf。Theirstructurehasabsolutelynothingincommonwithnettle-hairs，thosetaperingphialswhosehardpointsnapsoff，pouringanirritantfluidintothetinywound。
　　TheplantfromwhoseLatinname，Urtica，wederivethewordurticationborrowedthedesignofitsweaponfromthefangsofthevenomousserpents；
　　itobtainsitseffect，notbythewound，butbythepoisonintroducedintothewound。TheProcessionaryemploysadifferentmethod。Thehairs，whichhavenaughtresemblingtheampullaryreservoirofthenettle-hairs，mustbepoisonedonthesurface，liketheassegaisoftheKafirsandZulus。
　　Dotheyreallypenetratetheepidermis？Aretheylikethesavage’sjavelin，whichcannotbeextractedonceithasgonein？Withtheirbarbs，dotheyenterallthemoredeeplybecauseofthequiveringoftheoutragedflesh？Thereisnogroundforbelievinganythingofthekind。InvaindoIscrutinizetheinjuredspotthroughthemagnifying-glass；
　　Icanseenosignoftheimplanteddart。NeithercouldRé；aumur，whenanencounterwiththeOakProcessionarysethimscratchinghimself。
　　Hehadhissuspicions，butcouldstatenothingdefinitely。
　　No；despitetheirsharppointsandtheirbarbs，whichmakethem，underthemicroscope，suchformidablespears，theProcessionary’srussethairsarenotdartsdesignedtoimbedthemselvesintheskinandtoprovokeirritationbypricking。
　　Manycaterpillars，allmostinoffensive，haveacoatofbristleswhich，underthemicroscope，resolvethemselvesintobarbedjavelins，quiteharmlessinspiteoftheirthreateningaspect。Letmementionacoupleofthesepeaceablehalberdiers。
　　Earlyinspring，wesee，crossingthepaths，abriskly-movingcaterpillarwhoinspiresrepugnancebyhisferocioushairiness，whichrippleslikeripecorn。Theancientnaturalists，withtheirartlessandpicturesquenomenclature，calledhimtheHedgehog。Thetermisworthyofthecreature，which，inthemomentofdanger，rollsitselfuplikeaHedgehog，presentingitsspinyarmouronallsidestotheenemy。Onitsbackisadensemixtureofblackhairsandhairsofashen-gray；whileonthesidesandfore-partofthebodyisastiffmaneofbrightrusset。Black，greyorrusset，allthisfierce-lookingcoatisheavilybarbed。
　　Onehesitatestotouchthishorrorwiththefinger-tips。Still，encouragedbymyexample，seven-year-oldPaul，withhistenderchild’sskin，gathershandfulsoftherepulsiveinsectwithnomoreapprehensionthanifhewerepickingabunchofviolets。Hefillshisboxeswithit；herearsitonelm-leavesandhandlesitdaily，forheknowsthatfromthisfrightfulcreaturehewillonedayobtainasuperbMothCheloniacaja，LINN。，cladinscarletvelvet，withthelowerwingsredandtheupperwhite，sprinkledwithbrownspots。
　　Whatresultedfromthechild’sfamiliaritywiththeshaggycreature？
　　Notevenatraceofitchingonhisdelicateskin。Idonotspeakofmine，whichistannedbytheyears。
　　Intheosier-bedsofourlocalstream，therushingAygues，athornyshrubaboundswhich，attheadventofautumn，iscoveredwithaninfinityofverysourredberries。Itscrabbedboughs，whichbearbutlittleverdure，arehiddenundertheirclustersofvermilionballs。
　　ItisthesallowthornorseabuckthornHippophaë；rhamnoides。
　　InApril，averyhairybutratherprettycaterpillarlivesattheexpenseofthisshrub’sbuddingleaves。Hehasonhisbackfivedensetuftsofhair，setsidebysideandarrangedlikethebristlesofabrush，tuftsdeep-blackinthecentreandwhiteattheedges。Hewavestwodivergentplumesinfrontofhimandsportsathirdonhiscrupper，likeafeatherytail。Thesethreeareblackhair-pencilsofextremedelicacy。
　　HisgreyishMoth，flattenedmotionlessonthebark，stretcheshislongfore-legs，oneagainsttheother，infrontofhim。Youwouldtakethem，atafirstglance，forantennaeofexaggeratedproportions。ThisposeoftheextendedlimbshaswontheinsectthescientificlabelofOrgyia，arm’slength；andalsothevulgarandmoreexpressivedenominationofPatteé；tendue，oroutstretchedpaw。
　　LittlePaulhasnotfailed，withmyaid，toreartheprettybearerofthetuftsandbrushes。Howmanytimes，withhissensitivefinger，hashenotstrokedthecreature’sfurrycostume？Hefounditsofterthanvelvet。Andyet，enlargedunderthemicroscope，thecaterpillar’shairsarehorriblebarbedspears，nolessmenacingthanthoseoftheProcessionary。
　　Theresemblancegoesnofarther:handledwithoutprecautions，thetuftedcaterpillardoesnotprovokeevenasimplerash。Nothingcouldbemoreharmlessthanhiscoat。
　　Itisevident，then，thatthecauseoftheirritationlieselsewherethaninthebarbs。Ifthebarbedbristleswereenoughtopoisonthefingers，mosthairycaterpillarswouldbedangerous，fornearlyallhavespinybristles。
　　Wefind，onthecontrary，thatvirulenceisbestoweduponaverysmallnumber，whicharenotdistinguishedfromtherestbyanyspecialstructureofthehair。
　　Thatthebarbshaveaparttoplay，thatoffixingtheirritantatomupontheepidermis，ofkeepingitanchoredinitsplace，is，afterall，possible；buttheshootingpainscannotbyanymeansbecausedbythemereprickofsodelicateaharpoon。
　　Muchlessslender，thehairsclusteredintopadsonthepricklypearsareferociouslybarbed。Woetothefingersthathandlethiskindofvelvettooconfidently！Attheleasttouchtheyarepiercedwithharpoonswhoseextractioninvolvesaseveretaxuponourpatience。
　　Otherinconveniencethereislittleornone，fortheactionofthebarbisinthiscasepurelymechanical。Supposing——averydoubtfulthing——thattheProcessionary’shairscouldpenetrateourskin，theywouldactlikewise，onlywithlesseffect，iftheyhadmerelytheirsharppointsandtheirbarbs。Whatthendotheypossessinaddition？
　　Theymusthave，notinsidethem，likethehairsofthenettle，butoutside，onthesurface，anirritantagent；theymustbecoatedwithapoisonousmixture，whichmakesthemactbysimplecontact。
　　Letusremovethisvirus，bymeansofasolvent；andtheProcessionary’sdarts，reducedtotheirinsignificantmechanicalaction，willbeharmless。
　　Thesolvent，ontheotherhand，ridofallhairsbyfiltration，willbechargedwiththeirritantelement，whichweshallbeabletotestwithouttheagencyofthehairs。Isolatedandconcentrated，thestingingelement，farfromlosingbythistreatment，oughttogaininvirulence。Soreflectiontellsus。
　　Thesolventstriedareconfinedtothree:water，spiritsofwineandsulphuricether。Iemploythelatterbypreference，althoughtheothertwo，spiritsofwineespecially，haveyieldedsatisfactoryresults。Tosimplifytheexperiment，insteadofsubmittingtotheactionofthesolventtheentirecaterpillar，whowouldcomplicatetheextractwithhisfatsandhisnutritivejuices，Iprefertoemploythecastskinalone。
　　Ithereforecollect，ontheonehand，theheapofdryskinswhichthemoultofthesecondphasehasleftonthedomeofthesilkendwellingand，ontheotherhand，theskinswhichthecaterpillarshaverejectedintheircocoonsbeforebecomingchrysalids；andIleavethetwolotstoinfuse，separately，insulphuricetherfortwenty-fourhours。Theinfusioniscolourless。
　　Theliquid，carefullyfiltered，isexposedtospontaneousevaporation；
　　andtheskinsarerinsedwithetherinthefilter，severaltimesover。
　　Therearenowtwoteststobemade:onewiththeskinsandonewiththeproductofmaceration。Thefirstisasconclusiveascanbe。
　　Hairyasinthenormalstateandperfectlydried，theskinsofbothlots，drainedbytheether，producenottheslightesteffect，althoughIrubmyselfwiththem，withouttheleastcaution，atthejunctureofthefingers，aspotverysensitivetostinging。
　　Thehairsarethesameasbeforetheactionofthesolvent:theyhavelostnoneoftheirbarbs，oftheirjavelin-points；andyettheyareineffectual。
　　Theyproducenopainorinconveniencewhatever。Deprivedoftheirtoxicsmearing，thesethousandsofdartsbecomesomuchharmlessvelvet。TheHedgehogCaterpillarandtheBrushCaterpillararenotmoreinoffensive。
　　Thesecondtestismorepositiveandsoconclusiveinitspainfuleffectsthatonehardlylikestotryitasecondtime。Whentheetherealinfusionisreducedbyspontaneousevaporationtoafewdrops，Isoakinitaslipofblotting-paperfoldedinfour，soastoformasquaremeasuringsomethingoveraninch。Toounsuspectingofmyproduct，Idothingsonalavishscale，bothasregardsthesuperficialareaofmypoorepidermisandthequantityofthevirus。ToanyonewhomightwishtorenewtheinvestigationIshouldrecommendalessgenerousdose。Lastly，thesquareofpaper，thatnovelsortofmustard-plaster，isappliedtotheundersurfaceofthefore-arm。Athinwaterproofsheetingcoversit，topreventitfromdryingtoorapidly；andabandageholdsitinplace。
　　Forthespaceoftenhours，Ifeelnothing；thenIexperienceanincreasingitchandaburningsensationacuteenoughtokeepmeawakeforthegreaterpartofthenight。Nextday，aftertwenty-fourhoursofcontact，thepoulticeisremoved。Aredmark，slightlyswollenandveryclearlyoutlined，occupiesthesquarewhichthepoisonedpapercovered。
　　Theskinfeelssore，asthoughithadbeencauterized，andlooksasroughasshagreen。Fromeachofitstinypustulestricklesadropofserousfluid，whichhardensintoasubstancesimilarincolourtogum-arabic。
　　Thisoozingcontinuesforacoupleofdaysandmore。Thentheinflamationabates；thepain，hithertoverytrying，quietsdown；theskindriesandcomesoffinlittleflakes。Allisover，excepttheredmark，whichremainsforalongtime，sotenaciousinitseffectsisthisextractofProcessionary。
　　Threeweeksaftertheexperiment，thelittlesquareonthefore-armsubjectedtothepoisonisstilldiscoloured。
　　Forthusbrandingone’sself，doesoneatleastobtainsomesmallreward？
　　Yes。Alittletruthisthebalmspreaduponthewound；andindeedtruthisasovereignbalm。Itwillcomepresentlytosolaceusformuchgreatersufferings。
　　Forthemoment，thispainfulexperimentshowsusthattheirritationhasnotasitsprimarycausethehairinessoftheProcessionary。Hereisnohair，nobarb，nodart。Allofthathasbeenretainedbythefilter。
　　Wehavenothingnowbutapoisonousagentextractedbythesolvent，theether。Thisirritantelementrecalls，toacertainextent，thatofcantharides，whichactsbysimplecontact。Mysquareofpoisonedblotting-paperwasasortofplaster，which，insteadofraisingtheepidermisingreatblisters，makesitbristlewithtinypustules。
　　Thepartplayedbythebarbedhairs，thoseatomswhichtheleastmovementoftheairdisseminatesinalldirections，isconfinedtoconveyingtoourfaceandhandstheirritantsubstanceinwhichtheyareimpregnated。
　　Theirbarbsholdtheminplaceandthuspermitthevirustoact。Itisevenprobablethat，bymeansofslightscratcheswhichwouldotherwisepassunnoticed，theyassisttheactionofthestingingfluid。
　　ShortlyafterhandlingtheProcessionaries，adelicateepidermisbecomestumefied，redandpainful。Withoutbeingimmediate，theactionofthecaterpillarisprompt。Theextractmadewithether，ontheotherhand，causespainandrubefactiononlyafteralongishinterval。Whatdoesitneedtoproducemorerapidulceration？Toallappearances，theactionofthehairs。
　　Thedirectstingingcausedbythecaterpillarisnothinglikesoseriousasthatproducedbytheetherealextractconcentratedinafewdrops。Neverbefore，inmymostpainfulmisadventures，whetherwiththesilkenpursesortheirinhabitants，haveIseenmyskincoveredwithserouspustulesandpeelingoffinflakes。Thistimeitisaveritablesore，anythingbutpleasingtotheeye。
　　Theaggravationiseasilyexplained。Isoakedintheethersomefiftydiscardedskins。Thefewdropswhichremainedaftertheevaporationandwhichwereabsorbedbythesquareofblotting-paperrepresented，therefore，thevirulenceofasingleinsectfiftytimesincreased。Mylittleblistering-plasterwasequivalenttothecontactoffiftycaterpillarsatthesamespot。Thereisnodoubtthat，ifweleftthemtosteepinconsiderablenumbers，weshouldobtainextractsofreallyformidablestrength。Itisquitepossiblethatmedicalsciencewillonedaymakegooduseofthispowerfulcounter-irritant，whichisutterlydifferentfromcantharides。
　　Whethervoluntaryvictimsofourcuriosity，which，whileaffordingnoothersatisfactionthanthatofknowledge，exposesustoanintolerableitch，orsufferersthroughanaccident，whatcanwedotogivealittlerelieftotheirritationcausedbytheProcessionary？Itisgoodtoknowtheoriginoftheevil，butitwouldbebettertoapplyaremedy。
　　Oneday，withbothhandssorefromtheprolongedexaminationofanest，Itrywithoutsuccesslotionsofalcohol，glycerine，oilandsoapsuds。
　　Nothingdoesanygood。IthenrememberapalliativeemployedbyRé；aumuragainstthestingoftheOakProcessionary。Withouttellingushowhecametoknowofthestrangespecific，themasterrubbedhimselfwithparsleyandfeltagooddealthebetterforit。Headdsthatanyotherleafwouldprobablyassuagetheirritationinthesameway。
　　Thisisafittingoccasionforreopeningthesubject。Here，inacornerofthegarden，isparsley，greenandabundantasonecouldwish。Whatotherplantcanwecomparewithit？Ichoosethepurslain，thespontaneousguestofmyvegetable-beds。Mucilaginousandfleshyasitis，itreadilycrushes，yieldinganemollientliniment。Irubonehandwithparsleyandtheotherwithpurslain，pressinghardenoughtoreducetheleavestoapaste。Theresultdeservesattention。
　　Withtheparsley，theburningisalittlelessacute，itistrue，but，thoughrelieved，itpersistsforalongtimeyetandcontinuestroublesome。
　　Withthepurslain，thepettytortureceasesalmostatonceandsocompletelythatInolongernoticeit。Mynostrumpossessesincontestablevirtues。
　　Irecommenditquietly，withoutblatantadvertisement，toanyonewhomaybepersecutedbytheProcessionary。Foresters，intheirwaruponcaterpillars’
　　nests，shouldfindgreatrelieffromit。
　　Ihavealsoobtainedgoodresultswiththeleavesofthetomatoandthelettuce；and，withoutpursuingthisbotanicalsurveyfurther，Iremainconvinced，withReaumur，thatanytenderjuicyfoliagewouldpossessacertainefficacy。
　　Asforthemodeofactionofthisspecific，IadmitthatIdonotunderstandit，anymorethanIcanperceivethemodeofactionofthecaterpillar’svirus。Moliè；re’smedicalstudentexplainedthesoporificpropertiesofopiumbysaying:
　　"Quiaestineovirtusdormitavacujusestproprietassensusassoupire。"
　　Letussaylikewise:thecrushedherbcalmstheburningitchbecauseitpossessesacalmingvirtuewhosepropertyistoassuageitching。
　　Thequipisagooddealmorephilosophicalthanitlooks。Whatdoweknowofourremediesorofanything？Weperceiveeffects，butwecannotgetbacktotheircauses。
　　Inmyvillageandforsomedistancearoundit，thereisapopularbeliefthattorelievethepainofaWasp’sorBee’sstingallthatweneeddoistorubthepartstungwiththreesortsofherbs。Take，theysay，threekindsofherbs，thefirstthatcometohand，makethemintoabunchandrubhard。Theprescription，byallaccounts，isinfallible。
　　Ithoughtatfirstthatthiswasoneofthosetherapeuticabsurditieswhichhavetheirbirthinrusticimaginations。Aftermakingatrial，I
　　admitthatwhatsoundslikeanonsensicalremedysometimeshassomethinggenuineaboutit。FrictionwiththreekindsofherbsdoesactuallydeadenthestingoftheWasporBee。
　　Ihastentoaddthatthesamesuccessisachievedwithasingleherb；
　　andsotheresultagreeswithwhattheparsleyandpurslainhavetaughtusinrespectoftheirritationcausedbytheProcessionary。
　　Whythreeherbswhenoneisenough？Threeisthepreeminentlyluckynumber；itsmacksofwitchcraft，whichisfarfromdetractingfromthevirtuesoftheunguent。Allrusticmedicinehasatouchofmagicaboutit；andthereismeritindoingthingsbythrees。
　　Perhapsthespecificofthethreeherbsmayevendatebacktothemateriamedicaofantiquity。Dioscoridesrecommendstriphyllon:itis，hestates，goodforthebiteofvenomousserpents。Todeterminethiscelebratedthree-leavedplantexactlywouldnotbeeasy。Isitacommonclover？Thepsoralea，withitspitchyodour？Themenyanthes，oruck-bean，thatinmateofthechillypeat-bogs？Theoxalis，thewood-sorrelofthecountry-side？Wecannottellforcertain。Thebotanyofthosedayswasinnocentofthedescriptiveconscientiousnessofours。Theplantwhichactedasapoison-antidotegroupeditsleavesbythrees。Thatisitsessentialcharacteristic。
　　Againthecabalisticnumber，essentialtomedicalvirtuesasconceivedbythefirsthealers。Thepeasant，atenaciousconservative，haspreservedtheancientremedy，but，byahappyinspiration，haschangedthethreeoriginalleavesintothreedifferentherbs；hehaselaboratedthetriphyllonintothethreefoldfoliagewhichhecrushesontheBee’ssting。IseemtoperceiveacertainrelationbetweentheseartlesswaysandthecrushingofparsleyasdescribedbyRé；aumur。7，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916VII:THEARBUTUSCATERPILLAR
　　IHAVEnotfoundmanyspeciesofurticatingcaterpillarsinthesmallcornerofmyinvestigations。Iknowoftwoonly:thePineCaterpillarandtheArbutusCaterpillar。ThelatterbelongstothegenusLiparis。HisMoth，whoisaglorioussnowywhite，withthelastringsoftheabdomenbrightrusset，isverylikeLiparisauriflua，FAB。，fromwhomshediffersnotonlyinsize-sheissmaller——but，aboveall，inthefieldofoperationsselectedbyhercaterpillar。Isthespeciesclassifiedinourlists？Idonotknow；andreallyitishardlyworthwhiletoenquire。WhatdoesaLatinnamematter，whenonecannotmistaketheinsect？IshallbesparingofdetailconcerningtheArbutusCaterpillar，forheisfarlessinterestinginhishabitsthanthePineProcessionary。
　　Onlyhisravagesandhispoisondeserveseriousattention。
　　OntheSé；rignanhills，sunnyheightsuponwhichtheMediterraneanvegetationcomestoanend，thearbutus，orstrawberry-tree，abounds:
　　amagnificentshrub，withlustrousevergreenfoliage，vermilionfruit，roundandfleshyasstrawberries，andhangingclustersoflittlewhitebellsresemblingthoseofthelilyofthevalley。WhenthefrostscomeattheapproachofDecember，nothingcouldbemorecharmingthanthearbutus，deckingitsgayverdurewithbothfruitsandflowers，withcoralballsandplumplittlebells。Aloneofourflora，itcombinesthefloweringofto-daywiththeripeningofyesterday。
　　Thenthebright-redraspberries——thedarbouses，aswecallthemhere——belovedbytheBlackbird，growsoftandsweettothepalate。Thehousewivespluckthemandmakethemintopreservesthatarenotwithoutmerit。Asfortheshrubitself，whentheseasonforcuttinghascome，itisnot，despiteitsbeauty，respectedbythewoodman。Itserves，likeanytrivialbrushwood，inthemakingoffaggotsforheatingovens。Frequently，too，theshowyarbutusisravagedbyacaterpillaryetmoretobedreadedthanthewoodcutter。Afterthisgluttonhasbeenatit，itcouldnotlookmoredesolatehaditbeenscorchedandblackenedbyfire。
　　TheMoth，aprettylittle，snow-whiteBombyx，withsuperbantennaryplumesandacotton-wooltippetonherthorax，layshereggsonaleafofthearbutusand，insodoing，startstheevil。
　　Youseealittlecushionwithpointedends，ratherlessthananinchinlength；awhiteeiderdown，tingedwithrusset，thick，verysoftandformedofhairsfixedwithalittlegumbytheendthatpointstowardstheupperextremityoftheleaf。Theeggsaresunkinthethicknessofthissoftshelter。Theypossessametallicsheenandlooklikesomanynickelgranules。
　　HatchingtakesplaceinSeptember。Thefirstmealsaremadeattheexpenseofthenativeleaf；thelateronesattheexpenseoftheleavesallaround。
　　Onesurfaceonlyisnibbled，usuallytheupper；theotherremainsintact，trellisedbythenetworkofveins，whicharetoohornyforthenew-borngrubs。
　　Theconsumptionofleavesiseffectedwithscrupulouseconomy。Insteadofgrazingathazardandusingupthepasturageatthedictatesofindividualcaprice，theflockprogressesgraduallyfromthebasetothetipoftheleaf，withallheadsrangedinafrontalattack，almostinastraightline。
　　Notabiteistakenbeyondthisline，untilallthatliesonthissideofitiseatenup。
　　Asitadvances，theflockthrowsafewthreadsacrossthedenudedportion，wherenothingremainsbuttheveinsandtheepidermisoftheoppositesurface。
　　Thusiswovenagossamerveilservingasashelterfromthefierceraysofthesunandastheparachutewhichisessentialtotheseweaklings，whomapuffofwindwouldcarryaway。
　　Astheresultofamorerapiddesiccationontheravagedsurface，theleafsoonbeginstocurlofitsownaccord，curvingintoagondolawhichiscoveredbyacontinuousawningstretchedfromendtoend。Theherbageisthenexhausted。Theflockabandonsitandbeginsagainelsewhereinthenearneighbourhood。
　　Aftervarioustemporarypasturesofthiskind，inNovember，whenthecoldweatherisathand，thecaterpillarssettlepermanentlyattheendofabough。Nibbledonebyoneontheiruppersurfaces，theleavesoftheterminalbunchdrawclosetotheirneighbours，which，excoriatedintheirturn，dothesame，untilthewholeformsabundle，whichlooksasifithadbeenscorched，lashedtogetherwithmagnificentwhitesilk。Thisisthewinterhabitation，whencethefamily，stillveryfeeble，willnotissueuntilthefineweatherreturns。
　　Theassemblingofthisleafyframeworkisnotduetoanyspecialindustryonthecaterpillars’part；theydonotstretchtheirthreadsfromleaftoleafandthen，bypullingattheseropes，bringthevariouspiecesofthestructureintocontact。Itismerelytheresultofdesiccationonthenibbledsurfaces。Fixedcables，itistrue，solidlybindtogethertheleavesbroughtclosetooneanotherbythecontractionduetotheiraridity；buttheydonotinanywayplaythepartofamotivemechanismintheworkoftheassemblage。
　　Nohauling-ropesarehere，nocapstanstomovethetimbers。Thefeeblecreatureswouldbeincapableofsucheffort。Thethinghappensofitself。
　　Sometimesafloatingthread，theplaythingoftheair，enlacessomeadjacentleaf。Thischancefootbridgetemptstheexplorers，whohastentostriptheaccidentalprize；and，withoutotherlabour，yetonemoreleafbendsofitsownaccordandisaddedtotheenclosure。Forthemostpart，thehouseisbuiltbyeating；alodgingisprocuredbydintofbanqueting。
　　Acomfortablehouse，tightlyclosedandwell-caulked，proofagainstrainandsnow。We，toguardourselvesagainstdraughts，putsand-bagsagainstthecracksofourdoorsandwindows；theextravagantlittleArbutusCaterpillarappliespipingsofsilk-velvettohisshutters。Thingsshouldbecosyinside，howeverdampthefog。Inbadweather，theraindripsintomyhouse。Theleaf-dwellingknowsnothingofsuchtroubles，sotrueisitthatanimalsoftenenjoyadvantageswhichrelegatehumanindustrytothesecondrank。
　　Inthisshelterofsilkandfoliage，theworstthreeorfourmonthsoftheyeararepassedinastateofcompleteabstinence。Nooutings；notabiteoffood。InMarch，thistorporceases；andtherecluses，thosestarvingbellies，shifttheirquarters。
　　Thecommunitynowsplitsupintosquads，whichspreadthemselvesanyhowovertheadjacentverdure。Thisistheperiodofseriousdevastation。Thecaterpillarsnolongerconfinethemselvestonibblingonesurfaceoftheleaf；theirkeenappetitesdemandthewholeofit，downtothestalk。Andnow，stagebystage，haltbyhalt，thearbutusisshornbare。
　　Thevagabondsdonotreturntotheirwinterdwelling，whichhasbecometoocloselycramped。Theyreassembleingroupsandweave，here，thereandeverywhere，shapelesstents，temporaryhuts，abandonedforothersasthepasturageroundaboutbecomesexhausted。Thedenudedboughs，toallseemingravagedbyfire，takeonthelookofsqualiddrying-groundshungwithrags。
　　InJune，havingacquiredtheirfullgrowth，thecaterpillarsleavethearbutus-tree，descendtoearthandspinthemselves，amidthedeadleaves，aniggardlycocoon，inwhichtheinsect’shairstosomeextentsupplementitssilk。Amonthlater，theBombyxappears。
　　Inhisfinaldimensions，thecaterpillarmeasuresnearlyaninchandaquarterinlength。Hiscostumedoesnotlackrichnessororiginality:
　　ablackskinwithadoublerowoforangespecksontheback；longgreyhairsarrangedinbunches；short，snow-whitetuftsonthesides；andacoupleofbrown-velvetprotuberancesonthefirsttworingsoftheabdomenandalsoonthelastringbutone。
　　Themostremarkablefeature，however，consistsoftwotinycraters，alwaysopenwide；twocunninglyfashionedgobletswhichmighthavebeenwroughtfromadropofredsealing-wax。Thesixthandseventhsegmentsoftheabdomenaretheonlyonesthatbearthesevermiliongoblets，placedinthemiddleoftheback。Idonotknowthefunctionoftheselittlecups。Perhapstheyshouldberegardedasorgansofinformation，similartothePineProcessionary’sdorsalmouths。
　　TheArbutusCaterpillarismuchdreadedinthevillage。Woodcutters，faggot-binders，brushwood-gatherers，allareunanimousinrevilinghim。
　　Theyhavesuchapainfullyvividmemoryoftheirritationthat，whenI
　　listentothem，Icanhardlyrepressamovementoftheshoulderstorelievetheimaginaryitchinginthemiddleofmyback。Iseemtofeelthearbutus-faggot，ladenwithitsglowingrags，rubbingmybareskin。
　　Itis，itappears，adisagreeablejobtocutdowntheshrubalivewithcaterpillarsduringthehottestpartofthedayandtoshake，undertheblowsoftheaxe，thatsortofupas-tree，sheddingpoisoninitsshade。
　　Asforme，Ihavenocomplainttomakeofmyrelationswiththeravagerofthearbutus。Ihaveveryoftenhandledhim；Ihaveappliedhisfurtothetipsofmyfingers，myneckandevenmyface，forhoursatatime；
　　Ihaverippeduptheneststoextracttheirpopulationsforthepurposeofmyresearches；butIhaveneverbeeninconvenienced。
　　Saveinexceptionalcircumstances，theapproachofthemoultperhaps，thiswouldneedaskinlesstoughthanmine。
　　Thethinskinofachilddoesnotenjoythesameimmunity，aswitnesslittlePaul，who，havinghelpedmetoemptysomenestsandtocollecttheinhabitantswithmyforceps，wasforhoursscratchinghisneck，whichwasdottedwithredwheals。Myingenuousassistantwasproudofhissufferingsinthecauseofscience，whichresultedfromheedlessnessandalsoperhapsfrombravado。Intwenty-fourhours，thetroubledisappeared，withoutleavinganyseriousconsequences。
　　Allthishardlytallieswiththepainfulexperiencesofwhichthewoodcutterstalk。Dotheyexaggerate？Thatishardlycredible；theyaresounanimous。
　　Thensomethingmusthavebeenlackinginmyexperiments:thepropitiousmomentapparently，theproperdegreeofmaturityinthecaterpillar，thehightemperaturewhichaggravatesthepoison。
　　Toshowitselfinitsfullseverity，theurticationdemandsthecooperationofcertainundefinedcircumstances；andthiscooperationwaswanting。ChanceperhapswillonedayteachmemorethanIwanttoknow；
　　Ishallbeattackedinthemannerfamiliartothewoodcuttersandshallpassanightintorment，tossingandturningasthoughonabedoflivecoals。
　　WhatthedirectcontactofthecaterpillardidnotteachmetheartificesofchemistrywilldemonstratewithaviolencewhichIwasfarfromexpecting。
　　Itreatthecaterpillarwithether，justasItreatedthesloughofthePineProcessionary。Thenumberofthecreaturestakenfortheinfusion——theyareprettysmallasyet，arescarcelyhalfthesizewhichtheywillattainwhenmature——isaboutahundred。Afteracoupleofdays’maceration，I
　　filtertheliquidandleaveittoevaporatefreely。WiththefewdropsthatremainIsoakasquareofblotting-paperfoldedinfourandapplyittotheinnersurfaceofmyforearm，withathinrubbersheetandabandage。
　　ItisanexactrepetitionofwhatIdidwiththePineProcessionary。
　　Appliedinthemorning，theblisterhardlytakeseffectuntilthefollowingnight。Thenbydegreestheirritationbecomesunendurable；andtheburningsensationissoacutethatIamtormentedeverymomentwiththedesiretotearoffthebandage。HoweverIholdout，butatthecostofasleeplessnight。
　　HowwellInowunderstandwhatthewoodcutterstellme！Ihadlessthanasquareinchofskinsubjectedtothetorture。WhatwoulditbeifIhadmyback，shoulders，neck，faceandarmstormentedinthisfashion？Ipityyouwithallmyheart，youlabourerswhoaretroubledbythehatefulcreature。
　　Onthemorrow，theinfernalpaperisremoved。Theskinisredandswollen，coveredwithtinypimplesWhenceoozedropsofserousfluid。Forfivedaystheitchingpersists，withasharp，burningpain，andtherunningfromthepimplescontinues。Thenthedeadskindriesandcomesoffinscabs。
　　Allisover，savetheredness，whichisstillperceptibleamonthlater。
　　Thedemonstrationisaccomplished；theArbutusCaterpillar，capableasheisofproducing，undercertainconditions，thesameeffectswhichIobtainbyartificialmeans，fullydeserveshisodiousreputation。8，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916VIII:ANINSECTVIRUS
　　ONEstepforwardhasbeentaken，butonlyaverylittleoneasyet，intheproblemofthestingingcaterpillars。Thedrenchingwithetherteachesusthathairinessplaysaverysecondarypartinthematter。Withitsdustofbrokenbristles，whichtheleastbreathwaftsinalldirections，itbothersusbydepositingandfixingitsirritantcoatinguponus；butthisvirusdoesnotoriginateinthecreature’sfleece；itcomesfromelsewhere。
　　Whatisthesourceofit？
　　Iwillenterintoafewdetails。Perhaps，insodoing，Ishallbeofservicetothenovice。Thesubject，whichisverysimpleandsharplydefined，willshowushowonequestiongivesrisetoanother；howexperimentaltestsconfirmorupsethypotheses，whichare，asitwere，atemporaryscaffolding；
　　and，lastly，howlogic，thatsevereexaminer，leadsusbydegreestogeneralitieswhicharefarmoreimportantthananythingthatwewereledtoanticipateattheoutset。
　　And，firstofall，doesthePineProcessionarypossessaspecialglandularstructurewhichelaboratesthevirus，asdo，forinstance，thepoison-glandsoftheWaspsandBees？Bynomeans。Anatomyshowsthattheinternalstructureofthestingingcaterpillarissimilartothatoftheharmlessone。Thereisnothingmoreandnothingless。
　　Thepoisonousproduct，ofunlocalizedorigin，results，therefore，fromageneralprocessinwhichtheentireorganismisbroughtintoplay。Itshould，inconsequencebefoundintheblood，afterthemannerofureainhigheranimals。Thisisasuggestionofgraveimport，butafterallquitevaluelesswithouttheconclusiveverdictofactualexperiment。
　　FiveorsixProcessionaries，prickedwiththepointofaneedle，furnishmewithafewdropsofblood。Iallowthesetosoakintoasmallsquareofblotting-paper，whichIthenapplytomyfore-armwithawaterproofbandage。ItisnotwithoutacertainanxietythatIawaittheoutcomeoftheexperiment。Theresultwillshowwhethertheconclusionsalreadyforminginmymindwillreceiveasolidbasisorvanishintothinair。
　　Atalatehourofthenight，thepainwakesme，apainwhichthistimeisanintellectualjoy。Myanticipationswerecorrect。
　　Theblooddoesindeedcontainthevenomoussubstance。Itcausesitching，swelling，aburningsensation，anexudationofserumand，lastly，asheddingoftheskin。IlearnmorethanIhadhopedtolearn。Thetestismorevaluablethanthatofmerecontactwiththecaterpillarcouldhavebeen。Insteadoftreatingmyselfwiththesmallquantityofpoisonwithwhichthehairsaresmeared，IhavegonetothesourceoftheirritantsubstanceandI
　　therebygainanincreaseofdiscomfort。
　　Veryhappyinmysuffering，whichsetsmeonasafepath，Icontinuemyenquirybyarguingthus。thevirusinthebloodcannotbealivingsubstance，onethattakespartintheworkingoftheorganism；itisrather，likeurea，aformofdecay，anoffthrowofthevitalprocess，awasteproductwhichisexpelledasandwhenitforms。Ifthisbethecase，Ioughttofinditinthecaterpillar’sdroppings，whicharemadeupofboththedigestiveandtheurinaryresidues。
　　Letusdescribethenewexperiment，whichisnolesspositivethanthelast。Ileaveafewpinchesofverydrydroppings，suchasarefoundinabundanceintheoldnests，tosoakfortwodaysinsulphuricether。
　　Theliquid，colouredasitiswiththechlorophyllofthecaterpillar’sfood，turnsadirtygreen。ThenIrepeatpreciselytheprocesswhichI
　　mentionedwhenIwantedtoprovetheinnocuousnessofthehairsdeprivedoftheirpoisonousvarnish。Irefertoitasecondtimeinorderthoroughlytoexplainthemethodpursuedandtosaverepetitioninthevariousexperimentsundertaken。
　　Theinfusionisfiltered，spontaneouslyevaporatedandreducedtoafewdrops，withwhichIsoakmystinger。Thisconsistsofasmallpieceofblotting-paper，foldedinfourtoincreasethethicknessofthepadandtogiveitagreaterpowerofabsorption。Anareaofasquareinchorlesssuffices；insomecasesitiseventoomuch。Anoviceinthiskindofresearch-work，Iwastoolavishwiththeliniment；andinreturnformygenerosityIhadsuchabadtimethatImakeapointofwarninganyreaderdesirousofrepeatingtheexperimentuponhisownperson。
　　Fullysoaked，thesquareofpaperisappliedtothefore-arm，ontheinnersurface，wheretheskinismoretender。Asheetofrubbercoversitand，beingwaterproof，guardsagainstthelossofthepoison。Finally，alinenbandagekeepsthewholeinplace。
　　Ontheafternoonofthe4thofJune1897，amemorabledateforme，I
　　test，asIhavejustsaid，theethericextractoftheProcessionary’sdroppings。
　　Allnightlong，Ifeelaviolentitching，aburningsensationandshootingpains。Onthefollowingday，aftertwentyhoursofcontact，Iremovethedressing。
　　Thevenomousliquid，toolavishlyemployedinmyfearoffailure，hasconsiderablyoverflowedthelimitsofthesquareofpaper。Thepartswhichithastouchedandstillmoretheportioncoveredbythepadareswollenandveryred；moreover，inthelattercase，theskinisridged，wrinkledandmortified。Itsmartsalittleanditches；andthatisall。
　　Onthefollowingday，theswellingbecomesmorepronouncedandgoesdeepintothemuscles，which，whentouchedwiththefinger，throblikeaninflamedcheek。Thecolourisabrightcarmineandextendsallroundthespotwhichthepapercovered。Thisisduetotheescapeofsomeoftheliquid。Thereisaplentifuldischargeofserum，oozingfromthesoreintinydrops。Thesmartinganditchingincreaseandbecomesointense，especiallyduringthenight，that，togetalittlesleep，Iamdriventoemployapalliative，vaselinewithboraxandalintdressing。
　　Infivedays’time，ithasdevelopedintoahideousulcer，whichlooksmorepainfulthanitreallyis。Thered，swollenflesh，quiveringanddenudedofitsepidermis，provokescommiseration。Thepersonwhonightandmorningrenewsmydressingoflintandvaselineisalmostsickatthesight。
　　"Onewouldthink，"shesays，"thatthedogshadbeengnawingyourarm。
　　Idohopeyouwon’ttryanymoreofthosehorribledecoctions。"
　　Iallowmysympatheticnursetotalkawayandamalreadymeditatingfurtherexperiments，someofwhichwillbeequallypainful。Osacredtruth，whatcanrivalthypoweroverusmortals！Thouturnestmypettytormentintocontentment；thoumakestmerejoiceinmyflayedarm！WhatshallI
　　gainbyitall？Ishallknowwhyawretchedcaterpillarsetsusscratchingourselves。Nothingmore；andthatisenoughforme。
　　Threeweekslater，newskinisforming，butiscoveredalloverwithpainfullittlepimples。
　　Theswellingdiminishes；therednesspersistsandisstillverymarked。
　　Theeffectoftheinfernalpaperlastsalongtime。Attheendofamonth，Istillfeelanitching，aburningirritation，whichisintensifiedbythewarmthofthebed-clothes。Atlast，afortnightlater，allhasdisappearedbuttheredness，ofwhichIshallretainthemarksforalongtimeyet，thoughitgrowsgraduallyfainterandfainter。Itwilltakethreemonthsormoretovanishaltogether。
　　Wenowhavesomelightontheproblem:theProcessionary’svirusiscertainlyanoff-throwoftheorganicfactory，awasteproductofthelivingedifice。Thecaterpillardiscardsitwithhisexcrement。Butthematerialofthedroppingshasatwofoldorigin:thegreaterpartrepresentsthedigestiveresiduum；therest，inamuchsmallerproportion，iscomposedoftheurinaryproducts。Towhichofthetwodoesthevirusbelong？Beforegoingfarther，letuspermitourselvesadigressionwhichwillassistusinoursubsequentenquiries。LetusaskwhatadvantagestheProcessionaryderivesfromhisurticatingproduct。
　　Ialreadyheartheanswer:
　　"Itisameansofprotection，ofdefence。Withhispoisonedmane，herepelstheenemy。"
　　Idonotclearlyperceivethebearingofthisexplanation。Ithinkofthecreature’srecognizedenemies:ofthelarvaofCalosomasycophanta，，whichlivesinthenestsoftheProcessionaryoftheOakandgobblesuptheinhabitantswithneverathoughtoftheirburningfleece；oftheCuckoo，anothermightyconsumer，sowearetold，ofthesamecaterpillars，whogorgesonthemtothepointofimplantinginhisgizzardabristlingcoatoftheirhairs。
　　IamnotawareiftheProcessionaryofthePinepaysaliketribute。
　　Idoknowofatleastoneofhisexploiters。ThisisaDermestes，[note1]establisheshimselfinthesilkencityandfeedsupontheremainsofthedefunctcaterpillars。Thisghoulassuresusoftheexistenceofotherconsumers，allfurnishedwithstomachsexpresslyfashionedforsuchhighly-seasonedfare。Foreveryharvestoflivingcreaturesthereisalwaysaharvester。
　　No，thetheoryofaspecialvirus，expresslypreparedtodefendtheProcessionaryandhisemulatorsinurtication，isnotthelastwordonthesubject。Ishouldfinditdifficulttobelieveinsuchaprerogative。Whyhavethesecaterpillars，morethanothers，needofprotection？Whatreasonswouldmakeofthemacasteapart，endowedwithanexceptionaldefensivevenom？Thepartwhichtheyplayintheentomologicalworlddoesnotdifferfromthatofothercaterpillars，hairyorsmooth。
　　Itisthenakedcaterpillarswho，indefaultofamanecapableofstrikingaweintotheassailant，ought，onewouldthink，toarmthemselvesagainstdangerandimpregnatethemselveswithcorrosives，insteadofremainingameekandeasyprey。Isitlikelythattheshaggy，bristlingcaterpillarshouldanointhisfleecewithaformidablecosmeticandhissmooth-coatedkinsmanbeunfamiliarwiththechemicalpropertiesofthepoisonbeneathhissatinskin！Thesecontradictionsdonotinspireconfidence。
　　Havewenothere，rather，apropertycommontoallcaterpillars，smooth-skinnedorhairy？Amongthelatter，theremightbesome，justafew，who，undercertainspecialconditionswhichwillneedtobedefined，wouldbequicktorevealbyurticationthevenomousnatureoftheirorganicrefuse；theothers，thevastmajority，livingoutsidetheseconditions，eventhoughendowedwiththenecessaryproduct，wouldbeinexpertatthestingingbusinessandwouldnotproduceirritationbycontact。Inall，thesamevirusistobefound，resultingfromanidenticalvitalprocess。
　　Sometimesitisbroughtintoprominencebytheitchingwhichitproduces；
　　sometimes，indeedmostoften，itremainslatent，unrecognized，ifourartificesdonotintervene。
　　Whatshalltheseartificesbe？Somethingverysimple。IaddressmyselftotheSilkworm。Iftherebeaninoffensivecaterpillarintheworld，itiscertainlyhe。WomenandchildrentakehimupbythehandfulinourSilkworm-nurseries；
　　andtheirdelicatefingersarenonetheworseforit。Thesatin-skinnedcaterpillarisperfectlyinnocuoustoaskinalmostastenderashisown。
　　Butthislackofcausticvenomisonlyapparent。ItreatwithethertheexcretionsoftheSilkworm；andtheinfusion，concentratedintoafewdrops，istestedaccordingtotheusualmethod。Theresultiswonderfullydefinite。Asmartingsoreonthearm，similarinitsmodeofappearanceandinitseffectstothatproducedbythedroppingsoftheProcessionary，assuresmethatlogicwasright。
　　Yes，theviruswhichmakesonescratchsomuch，whichblistersandeatsawaytheskin，isnotadefensiveproductvestedinonlyafewcaterpillars。
　　Irecognizeit，withitsinvariableproperties，eveninacaterpillarwhichatfirstsightappearsasthoughitcouldnotpossessanythingofthekind。
　　TheSilkworm’svirus，besides，isnotunknowninmyvillage。Thecasualobservationofthepeasant-womanhasoutstrippedthepreciseobservationofthemanofscience。ThewomenandgirlsentrustedwiththerearingoftheSilkworm——themagnanarellesastheyarecalled——complainofcertaintribulationscaused，theysay，bylouvenndimagnan，theSilkworms’poison。Thistroubleconsistsofaviolentitchingoftheeyelids，whichbecomeredandswollen。Inthecaseofthemoresusceptible，thereisarashandtheskinpeelsoffthefore-arm，whichtheturned-upsleevesfailtoprotectduringwork。
　　Inowknowthecauseofthislittletrouble，mypluckymagnanarelles。Itisnotcontactwiththewormthatafflictsyou；youneedhavenofearofhandlinghim。Itisonlythelitterthatyouneeddistrust。There，jumbledupwiththeremainsofthemulberry-leaves，isacopiousmassofdroppings，impregnatedwiththesubstancewhichhasjustsopainfullyeatenintomyskin；thereandthereonlyislouverin，asyoucallit。
　　Itisareliefmerelytoknowthecauseofone’strouble；butIwillprovideyouwithanotherconsolation。Whenyouremovethelitterandrenewtheleaves，youshouldraisetheirritantdustaslittleaspossible；youshouldavoidliftingyourhandstoyourface，abovealltoyoureyes；anditisjustaswelltoturndownyoursleevesinordertoprotectyourarms。
　　Ifyoutaketheseprecautions，youwillsuffernounpleasantness。
　　ThesuccessfulresultobtainedwiththeSilkwormcausedmetoforeseeasimilarsuccesswithanycaterpillarthatImightcomeacross。Thefactsfullyconfirmedmyexpectations。Itestedthestercoralpelletsofvariouscaterpillars，notselected，butjustasthehazardofcollectingprovidedthem:theGreatTortoiseshell，theHeathFritillary，theLargeCabbageButterfly，theSpurgeHawk-moth，theGreatPeacockMoth，theDeath’s-headMoth，thePuss-moth，theTiger-mothandtheArbutusLiparis。Allmytests，withnotasingleexception，broughtaboutstinging，ofvariousdegreesofviolence，itistrue。Iattributethesedifferencesintheresulttothegreaterorlesserquantitiesofthevirusemployed，foritisimpossibletomeasurethedose。
　　Sotheurticatingexcretioniscommontoallthecaterpillars。Byaveryunexpectedreversionoftheusualorderofthings，thepopularrepugnanceiswell-founded；prejudicebecomestruth:allcaterpillarsarevenomous。
　　Wemustdrawadistinction，however:withthesamevenomousproperties，someareinoffensiveandothers，farlessnumerous，aretobefeared。Whencecomesthisdifference？
　　Inotethatthecaterpillarsmarkedoutasstingingliveincommunitiesandweavethemselvesdwellingsofsilk，inwhichtheystayforlongperiods。
　　Moreover，theyarefurry。OfthisnumberarethePineProcessionary，theOakProcessionaryandthecaterpillarsofvariousLipares。
　　Letusconsiderthefirst-namedinparticular。Hisnest，avoluminousbagspunatthetipofabranch，ismagnificentinitssilkywhiteness，ontheoutside；inside，itisadisgustingcesspit。Thecolonyremainsinitalldayandforthegreaterpartofthenight。
　　Itsalliesforthinprocessiononlyinthelatehoursoftwilight，tobrowseupontheadjacentfoliage。Thislonginternmentleadstoaconsiderableaccumulationofdroppingsintheheartofthedwelling。
　　Fromallthethreadsofthislabyrinthhangchapletsofthesedroppings；
　　thewallsareupholsteredwiththeminallthecorridors；thelittlenarrowchambersareencumberedwiththem。Fromanestthesizeofaman’sheadIhaveobtained，withasieve，overthree-quartersofapintofstercoralpellets。
　　Nowitisinthemidstofthisordurethatthecaterpillarsliveandhavetheirbeing；inthemidstofittheymove，swarmandsleep。Theresultsofthisuttercontemptfortherulesofcleanlinessareobvious。Certainly，theProcessionarydoesnotsoilhiscoatbycontactwiththosedrypellets；
　　heleaveshishomewithhiscostumeneatandglossy，suggestingnotasuspicionofuncleanliness。Nomatter:byconstantlyrubbingagainstthedroppings，hisbristlesareinevitablysmearedwithvirusandtheirbarbspoisoned。
　　Thecaterpillarbecomesirritant，becausehismanneroflifesubjectshimtoprolongedcontactwithhisownordure。
　　NowconsidertheHedgehogCaterpillar。Whyisheharmless，despitehisfierceandhirsuteaspect？Becausehelivesinisolationandisalwaysonthemove。Hismane，aptthoughitbetocollectandretainirritantparticles，willnevergiveustheitch，forthesimplereasonthatthecaterpillardoesnotlieonhisexcretions。Distributedalloverthefieldsandfarfromnumerous，owingtothecaterpillar’ssolitaryhabits，thedroppings，thoughpoisonous，cannottransfertheirpropertiestoafleecewhichdoesnotcomeintocontactwiththem。IftheHedgehoglivedinacommunity，inanestservingasacesspit，hewouldbetheforemostofourstingingcaterpillars。
　　Atfirstsight，thebarrack-roomsoftheSilkworm-nurseriesseemtofulfiltheconditionsnecessarytothesurfacevenomoftheworms。Eachchangeoflitterresultsintheremovalofbasketfulsofdroppingsfromthetrays。Overthisheaped-uporduretheSilk-wormsswarm。Howisitthattheydonotacquirethepoisonouspropertiesoftheirownexcrement？
　　Iseetworeasons。Inthefirstplace，theyarehairless；andabrushlikecoatmaywellbeindispensabletothecollectionofthevirus。Inthesecondplace，farfromlyinginthefilth，theyliveabovethesoiledstratum，beinglargelyseparatedfromitbythebedofleaves，whichisrenewedseveraltimesaday。Despitecrowding，thepopulationofatrayhasnothingthatcanbecomparedwiththeordinaryhabitsoftheProcessionary；andsoitremainsharmless，inspiteofitsstercoraltoxin。
　　Thesefirstenquiriesleadustoconclusionswhichthemselvesareveryremarkable。Allcaterpillarsexcreteanurticatingmatter，whichisidenticalthroughouttheseries。But，ifthepoisonistomanifestitselfandtocauseusthatcharacteristicitching，itisindispensablethatthecaterpillarshalldwellinacommunity，spendinglongperiodsinthenest，asilkenbagladenwithdroppings。Thesefurnishthevirus；thecaterpillar’shairscollectitandtransferittous。
　　Thetimehascometotackletheproblemfromanotherpointofview。
　　Isthisformidablematterwhichalwaysaccompaniestheexcretionsadigestiveresiduum？Isitnotratheroneofthosewastesubstanceswhichtheorganismengenderswhileatwork，wastesubstancesdesignatedbythegeneralappellationofurinaryproducts？
　　Toisolatetheseproducts，tocollectthemseparately，wouldscarcelybepracticable，ifwedidnothaverecoursetowhatfollowsonthemetamorphosis。
　　EveryMoth，onemergingfromherchrysalis，rejectsacopiousmixtureofuricacidandvarioushumoursofwhichverylittleisasyetknown。Itmaybecomparedwiththebrokenplasterofabuildingrebuiltonanewplanandrepresentstheby-productsofthemightylaboursaccomplishedinthetransfiguredinsect。Theseremainsareessentiallyurinaryproducts，withnoadmixtureofdigestedfoodstuffs。
　　TowhatinsectshallIapplyforthisresiduum？Chancedoesmanythings。
　　Icollect，fromtheoldelm-treeinthegarden，aboutahundredcuriouscaterpillars。Theyhavesevenrowsofpricklesofanamberyellow，asortofbushwithfourorfivebranches。IshalllearnfromtheButterflythattheybelongtotheGreatTortoiseshellVanessapolychloros，LIN。。
　　Rearedonelm-leavesunderawire-gauzecover，mycaterpillarsundergotheirtransformationtowardstheendofMay。Theirchrysalidsarespeckedwithbrownonawhitishgroundanddisplayontheundersurfacesixradiantsilveryspots，asortofdecorativetinsel，likesomanymirrors。Fixedbythetailwithasilkenpad，theyhangfromthetopofthedome，swingingattheleastmovementandemittingvividflashesoflightfromtheirreflectors。Mychildrenareamazedatthislivingchandelier。
　　ItisatreatforthemwhenIallowthemtocomeandadmireitinmyanimalstudio。
　　Anothersurpriseawaitsthem，thistimeatragicone，however。Afortnightlater，theButterfliesemerge。Ihaveplacedunderthecoveralargesheetofwhitepaper，whichwillreceivethedesiredproducts。Icallthechildren。
　　Whatdotheyseeonthepaper？
　　Largespotsofblood。Undertheirveryeyes，fromupthere，atthetopofthedome，abutterflyletsfallagreatreddrop:plop！Nojoyforthechildrento-day；anxietyrather，almostfear。
　　Isendthemaway，sayingtothem:
　　"Besureandremember，kiddies，whatyouhavejustseen；and，ifeveranyonetalkstoyouaboutshowersofblood，don’tbesillyandfrightened。
　　AprettyButterflyisthecauseofthoseblood-redstains，whichhavebeenknowntoterrifycountry-folk。Themomentsheisborn，shecastsout，intheformofaredliquid，theremainsofheroldcaterpillarbody，abodyremodelledandreborninabeautifulshape。Thatisthewholesecret。"
　　Whenmyartlessvisitorshavedeparted，Iresumemyexaminationoftherainofbloodfallingunderthecover。Stillclingingtotheshellofitschrysalis，eachTortoiseshellejectsandshedsuponthepaperagreatreddrop，which，ifleftstanding，depositsapowderypinksediment，composedofurates。Theliquidisnowadeepcrimson。
　　Whenthewholethingisperfectlydry，Icutoutofthespottedpapersomeofthericherstainsandsteepthebitsinether。Thespotsonthepaperremainasredasattheoutset；andtheliquidassumesalightlemontint。Whenreducedbyevaporationtoafewdrops，thisliquidprovidesmewithwhatIrequiretosoakmysquareofblotting-paper。
　　WhatshallIsaytoavoidrepeatingmyself？TheeffectsofthenewcausticarepreciselythesameasthosewhichIexperiencedwhenIusedthedroppingsoftheProcessionary。Thesameitching，thesameburning，thesameswellingwiththefleshthrobbingandinflamed，thesameserousexudation，thesamepeelingoftheskin，thesamepersistentredness，whichlingersforthreeorfourmonths，longaftertheulcerationitselfhasdisappeared。
　　Withoutbeingverypainful，thesoreissoirksomeandabovealllookssouglythatIswearnevertoletmyselfinforitagainHenceforth，withoutwaitingforthethingtoeatintomyflesh，IshallremovethecaterpillarplasterassoonasIfeelaconclusiveitching。
　　Inthecourseofthesepainfulexperiences，friendsupbraidmewithnothavingrecoursetotheassistanceofsomeanimal，suchastheGuinea-pig，thatstockvictimofthephysiologists。ItakenonoteoftheirreproachesTheanimalisastoic。Itsaysnothingofitssufferings。If，thetorturebeingalittletoointense，itcomplains，Iaminnopositiontointerpretitscriesexactlyortoattributethemtoadefiniteimpression。TheGuinea-pigwillnotsay:
　　"Itsmarts，ititches，itburns。"
　　Hewillsimplysay:
　　"Thathurts。"
　　AsIwanttoknowthedetailsofthesensationsexperienced，thebestthingistoresorttomyownskin，theonlywitnessonwhoseevidenceI
　　canrelyimplicitly。
　　Attheriskofprovokingasmile，Iwillventureonanotherconfession。
　　AsIbegintoseeintothemattermoreclearly，IhesitatetotortureordestroyasinglecreatureinGod’sgreatcommunity。Thelifeoftheleastoftheseisathingtoberespected。Wecantakeitaway，butwecannotgiveit。Peacetothoseinnocents，solittleinterestedinourinvestigations！
　　Whatdoesourrestlesscuriositymattertotheircalmandsacredignorance？
　　Ifwewishtoknow，letuspaythepriceourselvesasfaraspossible。
　　Theacquisitionofanideaiswellworththesacrificeofabitofskin。
　　TheElmTortoiseshell，withherrainofblood，mayleaveustoacertainextentindoubt。Mightnotthisstrangeredsubstance，withitsunusualappearance，containapoisonwhichislikewiseexceptional？IaddressmyselfthereforetotheMulberryBombyx，tothePineBombyxandtotheGreatPeacock。
　　IcollecttheuricexcretionsejectedbythenewlyhatchedMoths。
　　Thistime，theliquidiswhitish，sulliedhereandtherewithuncertaintints。Thereisnoblood-redcolouration；buttheresultisthesame。Thevirulentenergymanifestsitselfinthemostdefinitemanner。ThereforetheProcessionary’svirusexistsequallyinallcaterpillars，inallButterfliesandMothsemergingfromthechrysalis；andthisvirusisabyproductoftheorganism，aurinaryproduct。
　　Thecuriosityofourmindsisinsatiable。Themomentareplyisobtained，afreshquestionarises。WhyshouldtheLepidopteraalonebeendowedinthismanner？Theorganiclaboursaccomplishedwithinthemcannotdiffergreatly，astothenatureofthematerials，fromthosepresidingoverthemaintenanceoflifeinotherinsects。There。foretheseothersalsoelaborateaby-productwhichhasstingingpowers。Thiscanbeverified-andthatforthwith-withtheelementsatmydisposal。
　　ThefirstreplyisfurnishedbyCetoniafloricola，ofwhichBeetleIcollecthalfadozenchrysalidsfromaheapofleaveshalf-convertedintomould。Aboxreceivesmyfind，laidonasheetofwhitepaper，onwhichtheurinaryfluidoftheperfectinsectwillfallassoonasthecasketsarebroken。TheweatherisfavourableandIhavenotlongtowait。Thethingisdone:thematterrejectediswhite，theusualcolouroftheseresidua，inthegreatmajorityofinsects，atthemomentofthemetamorphosis。Thoughbynomeansabundant，itneverthelessprovokesonmyfore-armaviolentitching，togetherwithmortificationoftheskin，whichcomesoffinflakes。ThereasonwhyitdoesnotdisplayamoredistinctsoreisthatIjudgeditprudenttoendtheexperiment。
　　Theburninganditchingtellmeenoughastotheresultsofacontactundulyprolonged。
　　NowtotheHymenoptera。Ihavenotinmypossession，Iregrettosay，anyofthosewithwhommyrearing-chambersusedformerlytoprovideme，whetherHoney-beeorHuntingWasps。IhaveonlyaGreenSaw-fly，whoselarvalivesinnumerousfamiliesontheleavesofthealder。Rearedundercover，thislarvaprovidesmewithenoughtinyblackdroppingstofillathimble。Thatissufficient:theurticationisquitedefinite。
　　Itakenexttheinsectswithincompletetransformations。
　　MyrecentrearingshavegivenmequiteacollectionofexcretionsemanatingfromtheOrthoptera。IconsultthoseoftheVineEphippiger[note2]andtheGreatGreyLocust。Bothstingtoadegreewhichoncemoremakesmeregretmylavishhand。
　　Wewillbesatisfiedwiththis；indeedmyarmsdemandasmuch，for，tattooedwith，redsquares，theyrefusetomakeroomforfreshbrandings。
　　Theexamplesaresufficientlyvariedtoimposethefollowingconclusion:
　　theProcessionary’svirusisfoundinahostofotherinsects，apparentlyevenintheentireseries。Itisaurinaryproductinherentintheentomologicalorganism。
　　Thedejectionsofinsects，especiallythoseevacuatedattheendofthemetamorphosis，containorareevenalmostentirelycomposedofurates。
　　Canthestingingmaterialbetheinevitableassociateofuricacid？Itshouldthenformpartoftheexcrementofthebirdandthereptile，whichinbothcasesisveryrichinurates。Hereagainisasuspicionworthyofverificationbyexperiment。
　　Forthemomentitisimpossibleformetoquestionthereptile；itiseasy，ontheotherhand，tointerrogatethebird，whosereplywillsuffice。Iacceptwhatisofferedbychance:aninsectivorousbird，theSwallow，andagraminivorousbird，theGoldfinch。Well，theirurinarydejections，whencarefullyseparatedfromthedigestiveresidua，havenottheslighteststingingeffect。Thevirusthatcausesitchingsindependentthereforeofuricacid。Itaccompaniesitintheinsectclass，withoutbeingitsinvariableconcomitanteveryelsewhere。
　　Alaststepremainsforustotake，namely，toisolatethestingingelementandtoobtainitinquantitiespermittingofpreciseenquiriesintoitsnatureandproperties。Itseemstomethatmedicalsciencemightturntoaccountamaterialwhoseenergyrivalsthatofcantharides，ifitdoesnotexceedit。Thequestionappealstome。Iwouldgladlyreturntomybelovedchemistry；butIshouldwantreagents，apparatus，alaboratory，awholecostlyarsenalofwhichImustnotdream，afflictedasIamwithaterribleailment:impecuniosity，thesearcher’shabituallot。
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　　[note1]:ABacon-beetle——Translator’sNote。
　　[note2]:AspeciesofGrasshopper——Translator’sNote。9，TheLifeoftheCaterpillar，byJ。HenriFabre，1916TheLifeoftheCaterpillar，byJ。HenriFabre，1916IX:THEPSYCHES:THELAYING
　　INTHEspringtime，oldwallsanddustyroadsharbourasurpriseforwhosohaseyestosee。Tinyfaggots，fornoapparentreason，setthemselvesinmotionandmaketheirwayalongbysuddenjerks。Theinanimatecomestolife，theimmovablestirs。Howdoesthiscomeabout？Lookcloserandthemotivepowerwillstandrevealed。
　　Enclosedwithinthemovingbundleisafairlywell-developedcaterpillar，prettilystripedinblackandwhite。Seekingforfoodorperhapsforaspotwherethetransformationcanbeeffected，hehurriesalongtimidly，attiredinaqueerrig-outoftwigsfromwhichnothingemergesexcepttheheadandthefrontpartofthebody，whichisfurnishedwithsixshortlegs。Attheleastalarmhegoesrightinanddoesnotbudgeagain。Thisisthewholesecretofthelittleroamingbundleofsticks。
　　ThefaggotcaterpillarbelongstothePsychegroup，whosenameconveysanallusiontotheclassicPsyche，symbolicalofthesoul。Wemustnotallowthisphrasetocarryourthoughtstoloftierheightsthanisfitting。Thenomenclator，withhisrathercircumscribedviewoftheworld，didnottroubleaboutthesoulwheninventinghisdescriptivelabel。Hesimplywantedaprettyname；andcertainlyhecouldhavehitonnothingbetter。
　　Toprotecthimselffromtheweather，ourchilly，bare-skinnedPsychebuildshimselfaportableshelter，atravellingcottagewhichtheownerneverleavesuntilhebecomesaMoth。Itissomethingbetterthanahutonwheelswithathatchedrooftoit:itisahermit’sfrock，madeofanunusualsortoffrieze。InthevalleyoftheDanubethepeasantwearsagoatskincloakfastenedwithabeltofrushes。ThePsychedonsanevenmorerusticapparel。Hemakeshimselfasuitofclothesoutofhop-poles。
　　Itistruethat，beneaththisrudeconglomeration，whichwouldbearegularhair-shirttoaskinasdelicateashis，heputsathickliningofsilk。
　　TheClythraBeetlegarbshimselfinpottery；thisonedresseshimselfinafaggot。
　　InApril，onthewallsofmychiefobservatory，thatfamouspebblyacrewithitswealthofinsectlife，IfindthePsychewhoistofurnishmewithmymostcircumstantialanddetailedrecords。[note1]Heisatthisperiodinthetorporoftheapproachingmetamorphosis。
　　Aswecanaskhimnothingelseforthemoment，letuslookintotheconstructionandcompositionofhisfaggot。
　　Itisanotirregularstructure，spindle-shapedandaboutaninchandahalflong。Thepiecesthatcomposeitarefixedinfrontandfreeattheback，arearrangedanyhowandwouldformaratherineffectiveshelteragainstthesunandrainifthereclusehadnootherprotectionthanhisthatchedroof。
　　ThewordthatchissuggestedtomymindbyasummaryinspectionofwhatIsee，butitisnotanexactexpressioninthiscase。Onthecontrary，graminaceousstrawsarerare，tothegreatadvantageofthefuturefamily，which，asweshalllearnpresently，wouldfindnothingtosuittheminjointedplanks。Whatpredominatesisremnantsofverysmallstalks，light，softandrichinpith，suchasarepossessedbyvariousChicoriaceae。I
　　recognizeinparticularthefloralstemsofthemouse-earhawkweedandtheNimespterotheca。Nextcomebitsofgrass-leaves，scalytwigsprovidedbythecypress-treeandallsortsoflittlesticks，coarsematerialsadoptedforthelackofany-thingbetter。Lastly，ifthefavouritecylindricalpiecesfallshort，themantleissometimesfinishedoffwithanampleflouncedtippet，thatistosay，withfragmentsofdryleavesofanykind。
　　Incompleteasitis，thislistshowsusthatthecaterpillarapartfromhispreferenceforpithymorsels，hasnoveryexclusivetastes。Heemploysindifferentlyanythingthathecomesupon，providedthatitbelight，verydry，softenedbylongexposuretotheairandofsuitabledimensions。Allhisfinds，iftheycomeanywherenearhisestimates，areusedjustastheyare，withoutanyalterationsorsawingtoreducethemtotheproperlength。
　　ThePsychedoesnottrimthelathsthatgotoformhisroof；hegathersthemashefindsthem。Hisworkislimitedtoimbricatingthemoneaftertheotherbyfixingthematthefore-end。
　　Inordertolenditselftothemovementsofthejourneyingcaterpillarandinparticulartofacilitatetheactionoftheheadandlegswhenanewpieceistobeplacedinposition，thefrontpartofthesheathrequiresaspecialstructure。Hereacasingofbeamsisnolongerallowable，fortheirlengthandstiffnesswouldhampertheartisanandevenmakehisworkimpossible；whatisessentialhereisaflexibleneck，abletobendinalldirections。Theassemblageofstakesdoes，infact，endsuddenlyatsomedistancefrom。thefore-partandistherereplacedbyacollarinwhichthesilkenwoofismerelyhardenedwithverytinyligneousparticles，tendingtostrengthenthematerialwithoutimpairingitsflexibility。Thiscollar，whichgivesfreemovement，issoimportantthatallthePsychesmakeequaluseofit，howevermuchtherestoftheworkmaydiffer。Allcarry，infrontofthefaggotofsticks，ayieldingneck，softtothetouch，formedinsideofawebofpuresilkandvelvetedoutsidewithafinesawdustwhichthecaterpillarobtainsbycrushingwithhismandiblesanysortofdrystraw。
　　Asimilarvelvet，butlustrelessandfaded，apparentlythroughage，finishesthesheathattheback，intheformofaratherlong，bareappendix，openattheend。
　　Letusnowremovetheoutsideofthestrawenvelope，shreddingitpiecemeal。
　　Thedemolitiongivesusavaryingnumberofjoists:Ihavecountedasmanyaseightyandmore。Theruinthatremainsisacylindricalsheathwhereinwediscover，fromoneendtotheother，thestructurewhichweperceivedatthefrontandrear，thetwopartswhicharenaturallybare。Thetissueeverywhereisofverystoutsilk，whichresistswithoutbreakingwhenpulledbythefingers，asmoothtissue，beautifullywhiteinside，drabandwrinkledoutside，whereitbristleswithencrustedwoodyparticles。
　　Therewillbeanopportunitylatertodiscoverbywhatmeansthecaterpillarmakeshimselfsocomplicatedagarment，inwhicharelaidoneupontheother，inadefiniteorder，first，theextremelyfinesatinwhichisindirectcontactwiththeskin；next，themixedstuff，asortoffriezedustedwithligneousmatter，whichsavesthesilkandgivesconsistencytothework；lastly，thesurtoutofoverlappinglaths。
　　Whileretainingthisgeneralthreefoldarrangement，thescabbardoffersnotablevariationsofstructuraldetailinthedifferentspecies。
　　Here，forinstance，isasecondPsyche，[note2]themostbelatedofthethreewhichIhavechancedtocomeupon。
　　ImeethimtowardstheendofJune，hurryingacrosssomedustypathnearthehouses。Hiscasessurpassthoseofthepreviousspeciesbothinsizeandinregularityofarrangement。Theyformathickcoverlet，ofmanypieces，inwhichIrecognizeherefragmentsofhollowstalks，therebitsoffinestraw，withperhapsstrapsformedofbladesofgrass。Infrontthereisneveranymantillaofdeadleaves，atroublesomepieceoffinerywhich，withoutbeinginregularuse，isprettyfrequentinthecostumeofthefirst-namedspecies。Attheback，nolong，denudedvestibule。Savefortheindispensablecollarattheaperture，alltherestiscasedinlogs。
　　Thereisnotmuchvarietyaboutthething，but，whenallissaid，thereisacertaineleganceinitssternfaultlessness。
　　Thesmallestinsizeandsimplestindressisthethird，[note3]whoisverycommonattheendofwinteronthewalls，aswellasinthefurrowsofthebarksofgnarledoldtrees，betheyolive-trees，holm-oaks，elmsoralmostanyother。Hiscase，amodestlittlebundle，ishardlymorethantwo-fifthsofaninchinlength。Adozenrottenstraws，gleanedatrandomandfixedclosetooneanotherinaparalleldirection，represent，withthesilksheath，hiswholeoutlayondress。Itwouldbedifficulttoclotheone’sselfmoreeconomically。