LetusnowshowuptheDioxys。Atthetimewhentheworkofconstructionisinprogress，sheisanimpudentvisitorofthenests，exploitingwiththesameeffronterytheenormouscitiesoftheMason-
beeoftheShedsandthesolitarycupolasoftheMason-beeofthePebbles。Aninnumerablepopulation，comingandgoing，hummingandbuzzing，strikesherwithnoawe。OnthetileshangingfromthewallsofmyporchIseeher，withherredscarfroundherbody，stalkingwithsublimeassuranceovertheridgedexpanseofnests。Herblackschemesleavetheswarmprofoundlyindifferent；notoneoftheworkersdreamsofchasingheroff，unlesssheshouldcomebotheringtooclosely。Eventhen，allthathappensisafewsignsofimpatienceonthepartofthehustledBee。Thereisnoseriousexcitement，noeagerpursuitssuchasthepresenceofamortalenemymightleadustosuspect。Theyarethereintheirthousands，eacharmedwithherdagger；anyoneofthemiscapableofslayingthetraitress；andnotoneattacksher。Thedangerisnotsuspected。
Meanwhile，sheinspectstheworkyard，movesfreelyamongtheranksoftheMasonsandbideshertime。Iftheownerbeabsent，Iseeherdivingintoacell，comingoutagainamomentlaterwithhermouthsmearedwithpollen。Shehasbeentotrytheprovisions。Adaintyconnoisseur，shegoesfromonestoretoanother，takingamouthfulofhoney。Isitatitheforherpersonalmaintenance，orasampletestedforthebenefitofhercominggrub？Ishouldnotliketosay。WhatI
doknowisthat，afteracertainnumberofthesetastings，Icatchherstoppinginacell，withherabdomenatthebottomandherheadattheorifice。Thisisthemomentoflaying，unlessIammuchmistaken。
Whentheparasiteisgone，Iinspectthehome。Iseenothingabnormalonthesurfaceofthemass。Thesharpereyeoftheowner，whenshegetsback，seesnothingeither，forshecontinuesthevictuallingwithoutbetrayingtheleastuneasiness。Astrangeegg，laidontheprovisions，wouldnotescapeher。Iknowhowcleanshekeepsherwarehouse；Iknowhowscrupulouslyshecastsoutanythingintroducedbymyagency：aneggthatisnothers，abitofstraw，agrainofdust。So，accordingtomyevidenceandthatoftheChalicodoma，whichismoreconclusive，theDioxys’segg，ifitisreallylaidthen，isnotplacedonthesurface。
Isuspect，withouthavingyetverifiedmysuspicion——andIreproachmyselffortheneglect——Isuspectthattheeggisburiedintheheapofpollen-dust。WhenIseetheDioxyscomeoutofacellwithhermouthalloveryellowflour，perhapsshehasbeensurveyingthegroundandpreparingahiding-placeforheregg。WhatItakeforameretastingmightwellbeamoreseriousact。Thusconcealed，theeggescapestheeagleeyeoftheBee，whereas，ifleftuncovered，itwouldinevitablyperish，wouldbeflungontherubbishheapatoncebytheownerofthenest。WhentheSpottedSapygalayshereggonthatoftheBramble-dwellingOsmia，shedoesthedeedundercoverofdarkness，inthegloomofadeepwelltowhichnottheleastrayoflightcanpenetrate；andthemother，returningwithherpelletofgreenputtytobuildtheclosingpartition，doesnotseetheusurpinggermandisignorantofthedanger。Buthereeverythinghappensinbroaddaylight；
andthisdemandsmorecunninginthemethodofinstallation。
Besides，itistheonefavourablemomentfortheDioxys。IfshewaitsfortheMason-beetolay，itistoolate，fortheparasiteisnotabletobreakdowndoors，astheStelisdoes。Assoonashereggislaid，theMason-beeoftheShedscomesoutofhercellandatonceturnsroundandproceedstocloseitupwiththepelletofmortarwhichsheholdsreadyinhermandibles。Thematerialisemployedwithsuchmethodthattheactualsealingisdoneinamoment：theotherpellets，theobjectofrepeatedjourneys，willservemerelytoincreasethethicknessofthelid。ThechamberisinaccessibletotheDioxysfromthefirsttouchofthetrowel。HenceitisabsolutelynecessaryforhertoseetohereggbeforetheMason-beeoftheShedshasdisposedofhersandnolessnecessarytoconcealitfromtheMason’swatchfuleye。
ThedifficultiesarenotsogreatinthenestsoftheMason-beeofthePebbles。AfterthisBeehaslaidheregg，sheleavesitforatimetogoinsearchofthecementneededforclosingthecell；or，ifshealreadyholdsapelletinhermandibles，thisisnotenoughtosealitproperly，astheorificeislarger。Morepelletsareneededtowalluptheentranceentirely。TheDioxyswouldhavetimetostrikeherblowduringthemother’sabsences；buteverythingseemstosuggestthatshebehavesonthepebblesasshedoesonthetiles。Shestealsamarchbyhidingtheegginthemassofpollenandhoney。
WhatbecomesoftheMason’seggconfinedinthesamecellwiththeeggoftheDioxys？InvainhaveIopenednestsateveryseason；IhaveneverfoundavestigeoftheeggnorofthegrubofeitherChalicodoma。TheDioxys，whetherasalarvaonthehoney，orenclosedinitscocoon，orastheperfectinsect，wasalwaysalone。Therivalhaddisappearedwithoutatrace。Asuspicionthereuponsuggestsitself；andthefactsaresocompellingthatthesuspicionisalmostequaltoacertainty。Theparasiticgrub，whichhatchesearlierthantheother，emergesfromitshiding-place，fromthemidstofthehoney，comestothesurfaceand，withitsfirstbite，destroystheeggoftheMason-bee，astheSapygadoestheeggoftheOsmia。Itisanodious，butasupremelyefficaciousmethod。Normustwecryouttooloudlyagainstsuchfoulplayonthepartofanewborninfant：weshallmeetwithevenmoreheinoustacticslater。Thecriminalrecordsoflifearefullofthesehorrorswhichwedarenotsearchtoodeeply。Aninfinitesimalcreature，abarely-visiblegrub，withtheswaddling-
clothesofitseggstillclingingtoit，isledbyinstinct，atitsfirstinspiration，toexterminatewhateverisinitsway。
SotheMason’seggisexterminated。WasitreallynecessaryintheDioxys’interest？Notintheleast。ThehoardofprovisionsistoolargeforitsrequirementsinacelloftheChalicodomaoftheSheds；
howmuchmoresoinacelloftheChalicodomaofthePebbles！Sheeatsnotahalf，hardlyathirdofit。Therestremainsasitwas，untouched。Weseehere，inthedestructionoftheMason’segg，aflagrantwastewhichaggravatesthecrime。Hungerexcusesmanythings；
forlackoffood，thesurvivorsontheraftoftheMedusaindulgedinalittlecannibalism；butherethereisenoughfoodandtospare。Whenthereismorethansheneeds，whatearthlymotiveimpelstheDioxystodestroyarivalinthegermstage？Whycannotsheallowthelarva，hermess-mate，totakeadvantageoftheremainsandafterwardstoshiftforitselfasbestitcan？Butno：theMason-bee’soffspringmustneedsbestupidlysacrificedonthetopofprovisionswhichwillonlygrowmouldyanduseless！IshouldbereducedtothegloomylucubrationsofaSchopenhauerifIonceletmyselfbeginonparasitism。
SuchisabriefsketchofthetwoparasitesoftheChalicodomaofthePebbles，trueparasites，consumersofprovisionshoardedonbehalfofothers。TheircrimesarenotthebitteresttribulationsoftheMason-
bee。IfthefirststarvestheMason’sgrubtodeath，ifthesecondmakesitperishintheegg，thereareotherswhohaveamorepitiableendinginstorefortheworker’sfamily。WhentheBee’sgrub，allplumpandfatandgreasy，hasfinisheditsprovisionsandspunitscocoonwhereintosleeptheslumberakintodeath，thenecessaryperiodofpreparationforitsfuturelife，theseotherenemieshastentothenestswhosefortificationsarepowerlessagainsttheirhideouslyingeniousmethods。Soononthesleeper’sbodyliesanascentgrubwhichfeastsinallsecurityonthelusciousfare。Thetraitorswhoattackthelarvaeintheirlethargyarethreeinnumber：anAnthrax，aLeucopsisandamicroscopicdagger-wearer。（Monodontomeruscupreus。ForthisandtheAnthrax，cf。"TheLifeoftheFly"：chapters2and3。TheLeucopsisisaHymenopteron，theessayuponwhomformstheconcludingchapterofthepresentvolume。——Translator’sNote。）
Theirstorydeservestobetoldwithoutreticence；andIshalltellitlater。Forthemoment，Imerelymentionthenamesofthethreeexterminators。
Theprovisionsarestolen，theeggisdestroyed。Theyounggrubdiesofhunger，thelarvaisdevoured。Isthatall？Notyet。Theworkermustbeexploitedthoroughly，inherworkaswellasinherfamily。
Herearesomenowwhocovetherdwelling。WhentheMasonisconstructinganewedificeonapebble，heralmostconstantpresenceisenoughtokeeptheaspirantstofreelodgingsatadistance；herstrengthandvigilanceoverawewhosowouldannexhermasonry。If，inherabsence，onegreatlydaringthinksofvisitingthebuilding，theownersoonappearsuponthesceneandoustsherwiththemostdiscouraginganimosity。Shehasnoneedthentofeartheentranceofunwelcometenantswhilethehouseisnew。ButtheBeeofthePebblesalsousesolddwellingsforherlaying，aslongastheyarenottoomuchdilapidated。Intheearlystagesofthework，neighbourscompeteforthesewithaneagernesswhichshowsthevalueattachedtothem。
Facetoface，attimeswiththeirmandiblesinterlocked，nowbothrisingintotheair，nowcomingdownagain，thentouchinggroundandrollingovereachother，nextflyingupagain，forhoursonendtheywillwagebattleforthepropertyatissue。
Aready-madenest，afamilyheirloomwhichneedsbutalittlerestoring，isapreciousthingfortheMason，eversparingofhertime。WefindsomanyoftheoldhomesrepairedandrestockedthatI
suspecttheBeeoflayingnewfoundationsonlywhentherearenosecondhandneststobehad。Tohavethechambersofadomeoccupiedbyastrangerthereforemeansaseriousprivation。
NowseveralBees，howeverindustriousingatheringhoney，buildingparty-wallsandcontrivingreceptaclesforprovisions，arelesscleveratpreparingtheresortsinwhichthecellsaretobestacked。TheabandonedchambersoftheChalicodoma，nowlargerthantheywereoriginally，throughtheadditionofthehallofexit，arefirst-rateacquisitionsforthem。Thegreatthingistooccupythesechambersfirst，forherepossessionisninepartsofthelaw。Onceestablished，theMasonisnotdisturbedinherhome，whileshe，inherturn，doesnotdisturbthestrangerwhohassettleddownbeforeherinanoldnest，thepatrimonyofherfamily。ThedisinheritedoneleavestheBohemiantoenjoytheruinedmanorinpeaceandgoestoanotherpebbletoestablishherselfatfreshexpense。
Inthefirstrankofthesefreetenants，IwillplaceanOsmia（Osmiacyanoxantha，PEREZ）andaMegachile，orLeaf-cuttingBee（Megachileapicalis，SPIN。）（Cf。"Bramble-dwellersandOthers"：chapter8。——
Translator’sNote。），bothofwhomworkinMay，atthesametimeastheMason，whilebotharesmallenoughtolodgefromfivetoeightcellsinasinglechamberoftheChalicodoma，achamberincreasedbytheadditionofanouterhall。TheOsmiasubdividesthisspaceintoveryirregularcompartmentsbymeansofslanting，uprightorcurvedpartitions，subjecttothedictatesofspace。Thereisnoart，consequently，intheaccumulationoflittlecells；thearchitect’sonlytaskistousethebreadthatherdisposalinafrugalmanner。
Thematerialemployedforthepartitionsisagreen，vegetableputty，whichtheOsmiamustobtainbychewingtheshreddedleavesofaplantwhosenatureisstilluncertain。Thesamegreenpasteservesforthethickplugthatclosestheabode。Butinthiscasetheinsectdoesnotuseitunadulterated。Togivegreaterpowerofresistancetothework，itmixesanumberofbitsofgravelwiththevegetablecement。Thesematerials，whichareeasilypickedup，arelavishlyemployed，asthoughthemotherfearedlestsheshouldnotfortifysufficientlytheentrancetoherdwelling。Theyformasortofcoarsestucco，onthemoreorlesssmoothcupolaoftheChalicodoma；andthisunevenness，aswellasthegreencolouringofitsmortarofmasticatedleaves，atoncebetraystheOsmia’snest。Incourseoftime，undertheprolongedactionoftheair，thevegetableputtyturnsbrownandassumesadead-
leaftint，especiallyontheoutsideoftheplug；anditwouldthenbedifficultforanyonewhohadnotseenthemwhenfreshlymadetorecognizetheirnature。
TheoldnestsonthepebblesseemtosuitotherOsmiae。MynotesmentionOsmiaMorawitzi，PEREZ，andOsmiacyanea，KIRB。，ashavingbeenrecognizedinthesedwellings，althoughtheyarenotveryassiduousvisitors。Lastly，tocompletetheenumerationoftheBeesknowntomeasmakingtheirhomesintheMason’scupolas，ImustaddMegachileapicalis，whopilesineachcellahalf-dozenormorehoney-
potsconstructedwithdiskscutfromtheleavesofthewildrose，andanAnthidiumwhosespeciesIcannotstate，havingseennothingofherbutherwhitecottonsacks。
TheMason-beeoftheSheds，ontheotherhand，suppliesfreelodgingstotwospeciesofOsmiae，Osmiatricornis，LATR。，andOsmiaLatreillii，SPIN。，bothofwhomarequitecommon。TheThree-hornedOsmiafrequentsbypreferencethehabitationsoftheBeesthatbuildtheirnestsinpopulouscolonies，suchastheChalicodomaoftheShedsandtheHairy-footedAnthophora。Latreille’sOsmiaisnearlyalwaysfoundwiththeThree-hornedOsmiaattheChalicodoma’s。
Therealbuilderofthecityandtheexploiterofthelabourofothersworktogether，atthesameperiod，formacommonswarmandliveinperfectharmony，eachBeeofthetwospeciesattendingtoherbusinessinpeace。Theyshareandsharealike，asthoughbytacitagreement。IstheOsmiadiscreetenoughnottoputuponthegood-naturedMasonandtoutilizeonlyabandonedpassagesandwastecells？Ordoesshetakepossessionofthehomeofwhichtherealownerscouldthemselveshavemadeuse？Ileaninfavourofusurpation，foritisnotraretoseetheChalicodomaoftheShedsclearingoutoldcellsandusingthemasdoeshersisterofthePebbles。Bethisasitmay，allthislittlebusyworldliveswithoutstrife，somebuildinganew，othersdividinguptheolddwelling。
ThoseOsmiae，onthecontrary，whoaretheself-invitedguestsoftheMason-beeofthePebblesarethesoleoccupantsofthedome。Thecauseofthisisolationliesintheunsociabletemperoftheproprietress。
Theoldnestdoesnotsuitherfromthemomentthatsheseesitoccupiedbyanother。Insteadofgoingshares，shepreferstoseekelsewhereadwellingwhereshecanworkinsolitude。HergracioussurrenderofamostexcellentlodginginfavourofastrangerwhowouldbeincapableofofferingtheleastresistanceifadisputearoseprovesthegreatimmunityenjoyedbytheOsmiainthehomeoftheworkerwhomsheexploits。ThecommonandpeacefulswarmingoftheMason-beeoftheShedsandthetwocell-borrowingOsmiaeprovesitinastillmorepositivefashion。Thereisneverafightfortheacquisitionofanother’sgoodsorthedefenceofone’sownproperty；
neverabrawlbetweenOsmiaeandChalicodomae。Robberandrobbedliveonthemostneighbourlyterms。TheOsmiaconsidersherselfathome；
andtheotherdoesnothingtoundeceiveher。Iftheparasites，sodeadlytotheworkers，moveaboutintheirveryrankswithimpunity，withoutarousingthefaintestexcitement，anequallycompleteindifferencemustbeshownbythedispossessedownerstothepresenceoftheusurpersintheiroldhomes。IshouldbegreatlyputtoitifI
wereaskedtoreconcilethiscalmnessonthepartoftheexpropriatedonewiththeruthlesscompetitionthatissaidtoswaytheworld。
FashionedsoastoinstalherselfintheMason’sproperty，theOsmiameetswithapeacefulreceptionfromher。Myfeebleeyescanseenofurther。
Ihavenamedtheprovision-thieves，thegrub-murderersandthehouse-
grabberswholevytributeontheMason-bee。Doesthatendthelist？
Notatall。Theoldnestsarecitiesofthedead。TheycontainBeeswho，onachievingtheperfectstate，wereunabletoopentheexit-doorthroughthecementandwhowitheredintheircells；theycontaindeadlarvae，turnedintoblack，brittlecylinders；untouchedprovisions，bothmouldyandfresh，onwhichtheegghascometogrief；tatteredcocoons；shredsofskins；relicsofthetransformation。
IfweremovethenestoftheChalicodomaoftheShedsfromitstile——anestsometimesquiteeightinchesthick——wefindliveinhabitantsonlyinathinouterlayer。Alltheremainder，thecatacombsofpastgenerations，isbutahorribleheapofdead，shrivelled，ruined，decomposedthings。Intothissub-stratumoftheancientcitytheunreleasedBees，theuntransformedlarvaefallasdust；herethehoney-storesofoldgosour，heretheuneatenprovisionsarereducedtomould。
Threeundertakers，allmembersoftheBeetletribe，aClerus，aPtinusandanAnthrenus，battenontheseremains。ThelarvaeoftheAnthrenusandthePtinusgnawtheashesofthecorpses；thelarvaoftheClerus，withtheblackheadandtherestofitsbodyaprettypink，appearedtometobebreakingintotheoldjam-potsfilledwithrancidhoney。
Theperfectinsectitself，garbedinvermilionwithblueornaments，isfairlycommononthesurfaceoftheclayslabsduringtheworkingseason，strollingleisurelythroughtheyardtotastehereandtherethedropsofhoneyoozingfromsomecrackedpot。Notwithstandinghisshowylivery，sounliketheworkers’sombrefrieze，theChalicodomaeleavehiminpeace，asthoughtheyrecognizedinhimthescavengerwhosedutyitistokeepthesewerswholesome。
Ravagedbythepassingyears，theMason’shomeatlastfallsintoruinandbecomesahovel。Exposedasitistothedirectactionofwindandweather，thedomebuiltuponapebblechipsandcracks。Torepairitwouldbetooirksome，norwouldthatrestoretheoriginalsolidityoftheshakyfoundation。Betterprotectedbythecoveringofaroof，thecityoftheshedsresistslonger，withouthoweverescapingeventualdecay。Thestoreyswhicheachgenerationaddstothoseinwhichitwasbornincreasethethicknessandtheweightoftheedificeinalarmingproportions。Themoistureofthetilefiltersintotheoldestlayers，wrecksthefoundationsandthreatensthenestwithaspeedyfall。Itistimetoabandonforgoodthehousewithitscracksandrents。
Thereuponthecrumblingapartments，onthepebbleaswellasonthetile，becomethehomeofacampofgypsieswhoarenotparticularwheretheyfindashelter。Theshapelesshovel，reducedtoafragmentofawall，findsoccupants，fortheMason’sworkmustbeexploitedtotheutmostlimitsofpossibility。Intheblindalleys，allthatremainsoftheformercells，Spidersweaveawhite-satinscreen，behindwhichtheylieinwaitforthepassinggame。Innookswhichtheyrepairinsummaryfashionwithearthenembankmentsorclaypartitions，HuntingWasps——PompiliandTripoxyla——storeupsmallmembersoftheSpidertribe，includingsometimestheWeavingSpiderswholiveinthesameruins。
IhavesaidnothingyetoftheChalicodomaoftheShrubs。Mysilenceisnotduetonegligence，buttothecircumstancethatIamalmostdestituteoffactsrelatingtoherparasites。OfthemanynestswhichIhaveopenedinordertostudytheirinhabitants，onlyonesofarhasbeeninvadedbystrangers。Thisnest，thesizeofalargewalnut，wasfixedonapomegranate-branch。Itcomprisedeightcells，ofwhichsevenwereoccupiedbytheChalicodoma，andtheeighthbyalittleChalcis，theplagueofawholehostoftheBee-tribe。Apartfromthisinstance，whichwasnotaveryseriouscase，Ihaveseennothing。Inthoseaerialnests，swingingattheendofatwig，notaDioxys，aStelis，anAnthrax，aLeucopsis，thosedreadravagersoftheothertwoMasons；neveranyOsmiae，MegachilesorAnthidia，thoselodgersintheoldbuildings。
Theabsenceofthelatteriseasilyexplained。TheChalicodoma’smasonrydoesnotlastlongonitsfrailsupport。Thewinterwinds，whentheshelterofthefoliagehasdisappeared，musteasilybreakthetwig，whichislittlethickerthanastrawandliabletogivewaybyreasonofitsheavyburden。Threatenedwithanearlyfall，ifitisnotalreadyontheground，lastyear’sdwellingisnotrestoredtoservetheneedsofthepresentgeneration。Thesamenestdoesnotservetwice；andthisdoesawaywiththeOsmiaeandwiththeirrivalsintheartofutilizingoldcells。
Theelucidationofthispointdoesnotremovetheobscurityofthenext。Icanseenothingtoaccountfortheabsenceoratleasttheextremerarenessofusurpersofprovisionsandconsumersofgrubs，bothofwhomareveryindifferenttotheneworoldconditionsofthenest，solongasthecellsarewellstocked。CanitbethattheloftypositionoftheedificeandtheshakysupportofthetwigarousedistrustintheDioxysandothermalefactors？Forlackofabetterexplanation，Iwillleaveitatthat。
Ifmyideaisnotanemptyfancy，wemustadmitthattheChalicodomaoftheShrubswassingularlywell-inspiredinbuildinginmid-air。Youhaveseenofwhatmisfortunestheothertwoarevictims。IfItakeacensusofthepopulationofatile，manyatimeIfindtheDioxysandtheMason-beeinalmostequalproportions。Theparasitehaswipedouthalfthecolony。Tocompletethedisaster，itisnotunusualforthegrub-eaters，theLeucopsisandherrival，thepygmyChalcis，tohavedecimatedtheotherhalf。IsaynothingofAnthraxsinuata，whomI
sometimesseecomingfromthenestsoftheChalicodomaoftheSheds；
herlarvapreysontheThree-hornedOsmia，theMason-bee’svisitor。
Allsolitarythoughshebeonherboulder，whichwouldseemtheproperthingtokeepawayexploiters，thescourgeofdensepopulations，theChalicodomaofthePebblesisnolesssorelytried。Mynotesaboundincasessuchasthefollowing：oftheninecellsinonedome，threeareoccupiedbytheAnthrax，twobytheLeucopsis，twobytheStelis，onebytheChalcisandtheninthbytheMason。Itisasthoughthefourmiscreantshadjoinedforcesforthemassacre：thewholeoftheBee’sfamilyhasdisappeared，allbutoneyoungmothersavedfromthedisasterbyherpositioninthecentreofthecitadel。Ihavesometimesstuffedmypocketswithnestsremovedfromtheirpebbleswithoutfindingasingleonethathasnotbeenviolatedbyoneorotherofthemalefactorsandoftenerstillbyseveralofthematatime。Itisalmostaneventformetofindanestintact。Afterthesefunerealrecords，Iamhauntedbyagloomythought：thewealofonemeansthewoeofanother。
CHAPTER11。THELEUCOPSES。
（Thischaptershouldbereadinconjunctionwiththeessaysentitled"TheAnthrax"and"LarvalDimorphism"，formingchapters2and4of"TheLifeoftheFly。"——Translator’sNote。）
LetusvisitthenestsofChalicodomamurariainJuly，detachingthemfromtheirpebbleswithasidewardblow，asIexplainedwhentellingthestoryoftheAnthrax。TheMason-bee’scocoonswithtwoinhabitants，onedevouring，theotherinprocessofbeingdevoured，arenumerousenoughtoallowmetogathersomedozensinthecourseofamorning，beforethesunbecomesunbearablyhot。Wewillgiveasmarttaptotheflintssoastoloosentheclaydomes，wraptheseupinnewspapers，fillourboxandgohomeasfastaswecan，fortheairwillsoonbeasfieryasthedevil’skitchen。
Inspection，whichiseasierintheshadeindoors，soontellsusthat，thoughthedevouredisalwaysthewretchedMason-bee，thedevourerbelongstotwodifferentspecies。Intheonecase，thecylindricalform，thecreamy-whitecolouringandthelittlenippleconstitutingtheheadrevealtousthelarvaoftheAnthrax，whichdoesnotconcernusatpresent；intheother，thegeneralstructureandappearancebetraythegrubofsomeHymenopteron。TheMason’ssecondexterminatoris，infact，aLeucopsis（Leucopsisgigas，FAB。），amagnificentinsect，strippedblackandyellow，withanabdomenroundedattheendandhollowedout，asisalsotheback，intoagroovetocontainalongrapier，asslenderasahorsehair，whichthecreatureunsheathesanddrivesthroughthemortarrightintothecellwhereitproposestoestablishitsegg。Beforeoccupyingourselveswithitscapacitiesasaninoculator，letuslearnhowitslarvalivesintheinvadedcell。
Itisahairless，legless，sightlessgrub，easilyconfused，byinexperiencedeyes，withthoseofvarioushoney-gatheringHymenoptera。
Itsmoreapparentcharacteristicsconsistofacolouringlikethatofrancidbutter，ashinyandasitwereoilyskinandasegmentationaccentuatedbyaseriesofmarkedswellings，sothat，whenlookedatfromtheside，thebackisveryplainlyindented。Whenatrest，thelarvaislikeabowbendingroundatonepoint。Itismadeupofthirteensegments，includingthehead。Thishead，whichisverysmallcomparedwiththerestofthebody，displaysnomouth-partunderthelens；atmostyouseeafaintredstreak，whichcallsforthemicroscope。Youthendistinguishtwodelicatemandibles，veryshortandfashionedintoasharppoint。Asmallroundmouth，withafinepiercerontherightandleft，isallthatthepowerfulinstrumentreveals。Asformybestsinglemagnifying-glasses，theyshowmenothingatall。Ontheotherhand，wecanquiteeasily，withoutarmingtheeyewithalens，perceivethemouth-apparatus——andparticularlythemandibles——ofeitherahoney-eater，suchasanOsmia，ChalicodomaorMegachile，oragame-eater，suchasaScolia，AmmophilaorBembex。
Allthesepossessstoutpincers，capableofgripping，grindingandtearing。ThenwhatisthepurposeoftheLeucopsis’invisibleimplements？Hismethodofconsumingwilltellus。
Likehisprototype，theAnthrax，theLeucopsisdoesnoteattheChalicodoma-grub，thatistosay，hedoesnotbreakitupintomouthfuls；hedrainsitwithoutopeningitanddiggingintoitsvitals。Inhimagainweseeexemplifiedthatmarvellousartwhichconsistsinfeedingonthevictimwithoutkillingituntilthemealisover，soasalwaystohaveaportionoffreshmeat。Withitsmouthassiduouslyappliedtotheunhappycreature’sskin，thelethalgrubfillsitselfandwaxesfat，whilethefosteringlarvacollapsesandshrivels，retainingjustenoughlife，however，toresistdecomposition。Allthatremainsofthedecantedcorpseistheskin，which，whensoftenedinwaterandblownout，swellsintoaballoonwithouttheleastescapeofgas，thusprovingthecontinuityoftheintegument。Allthesame，theapparentlyunpuncturedbladderhaslostitscontents。ItisarepetitionofwhattheAnthraxhasshownus，withthisdifference，thattheLeucopsisseemsnotsowellskilledinthedelicateworkofabsorbingthevictim。InsteadofthecleanwhitegranulewhichisthesoleresiduewhentheFlyhasfinishedherjoint，theinsectwiththelongprobehasaplatefulofleavings，notseldomsoiledwiththebrownishtingeoffoodthathasgonebad。Itwouldseemthat，towardstheend，theactofconsumptionbecomesmoresavageanddoesnotdisdaindeadmeat。IalsonoticethattheLeucopsisisnotabletogetupfromdinnerortositdowntoitagainasreadilyastheAnthrax。Ihavesometimestoteasehimwiththepointofahair-pencilinordertomakehimletgo；and，oncehehasleftthejoint，hehesitatesalittlebeforeputtinghismouthtoitagain。Hisadhesionisnotthemereresultofakisslikethatofacupping-
glass；itcanonlybeexplainedbyhooksthatneedreleasing。
Inowseetheuseofthemicroscopicmandibles。Thosetwodelicatespikesareincapableofchewinganything，buttheymayverywellservetopiercetheepidermiswithanaperturesmallerthanthatmadebythefinestneedle；anditisthroughthispuncturethattheLeucopsissucksthejuicesofhisprey。Theyareinstrumentsmadetoperforatethebagoffatwhichslowly，withoutsufferinganyinternalinjury，isemptiedthroughanopeningrepeatedhereandthere。TheAnthrax’
cupping-glassisherereplacedbypiercersofexceedingsharpnessandsoshortthattheycannothurtanythingbeyondtheskin。Thusdoweseeinoperation，withadifferentsortofimplements，thatwisesystemwhichkeepstheprovisionsfreshfortheconsumer。
Itishardlynecessarytosay，tothosewhohavereadthestoryoftheAnthrax，thatthiskindoffeedingwouldbeimpossiblewithavictimwhosetissuespossessedtheirfinalhardness。TheMason-bee’sgrubisthereforeemptiedbytheLeucopsis’larvawhileitisinasemifluidstateanddeepinthetorporofthenymphosis。ThelastfortnightinJulyandthefirstfortnightinAugustarethebesttimestowitnesstherepast，whichIhaveseengoingonfortwelveandfourteendays。
Later，wefindnothingintheMason-bee’scocoonexcepttheLeucopsis’
larva，gloriouslyfat，and，byitsside，asortofthin，rancidrasher，theremainsofthedeceasedwet-nurse。ThingsthenremainastheyareuntilthehotpartofthefollowingsummeroratleastuntiltheendofJune。
Thenappearsthenymph，whichteachesusnothingstriking；andatlasttheperfectinsect，whosehatchingmaybedelayeduntilAugust。ItsexitfromtheMason’sfortresshasnolikenesstothestrangemethodemployedbytheAnthrax。Endowedwithstoutmandibles，theperfectinsectsplitstheceilingofitsabodebyitselfwithoutmuchdifficulty。Atthetimeofitsdeliverance，theMason-bees，whoworkinMay，havelongdisappeared。Thenestsonthepebblesareallclosed，theprovisioningisfinished，thelarvaearesleepingintheiryellowcocoons。AstheoldnestsareutilizedbytheMasonsolongastheyarenottoomuchdilapidated，thedomewhichhasjustbeenvacatedbytheLeucopsis，nowmorethanayearold，hasitsothercellsoccupiedbytheBee’schildren。Thereishere，withoutseekingfarther，afatlivingfortheLeucopsis’offspringwhichshewellknowshowtoturntoprofit。Itdependsbutonherselftomakethehouseinwhichshewasbornintotheresidenceofherfamily。Besides，ifshehasafancyfordistantexploration，claydomesaboundintheharmas。Theinoculationoftheeggsthroughthewallswillbeginshortly。Beforewitnessingthiscuriousperformance，letusexaminetheneedlethatistoeffectit。
Theinsect’sabdomenishollowed，atthetop，intoafurrowthatrunsuptothebaseofthethorax；theend，whichisbroaderandrounded，hasanarrowslit，whichseemstodividethisregionintotwo。Thewholethingsuggestsapulleywithafinegroove。Whenatrest，theinoculating-needleorovipositorremainspackedintheslitandthefurrow。Thedelicateinstrumentthusalmostcompletelyencirclestheabdomen。Underneath，onthemedianline，weseealong，dark-brownscale，pointed，keel-shaped，fixedbyitsbasetothefirstabdominalsegment，withitssidesprolongedintomembranouswingswhicharefastenedtightlytotheinsect’sflanks。Itsfunctionistoprotecttheunderlyingregion，asoft-walledregioninwhichtheprobehasitssource。Itisacuirass，alidwhichprotectsthedelicatemotor-
machineryduringperiodsofinactivitybutswingsfrombacktofrontandliftswhentheimplementhastobeunsheathedandused。
Wewillnowremovethislidwiththescissors，soastohavethewholeapparatusbeforeoureyes，andthenraisetheovipositorwiththepointofaneedle。Thepartthatrunsalongthebackcomesloosewithouttheslightestdifficulty，butthepartembeddedinthegrooveattheendoftheabdomenoffersaresistancethatwarnsusofacomplicationwhichwedidnotnoticeatfirst。Thetool，infact，consistsofthreepieces，acentralpiece，orinoculating-filament，andtwoside-pieces，whichtogetherconstituteascabbard。Thetwolatteraremoresubstantial，arehollowedoutlikethesidesofagrooveand，whenuniting，formacompletegrooveinwhichthefilamentissheathed。Thisbivalvularscabbardadhereslooselytothedorsalpart；but，fartheron，atthetipoftheabdomenandunderthebelly，itcannolongerbedetached，asitsvalvesareweldedtotheabdominalwall。Here，therefore，wefind，betweenthetwojoinedprotectingparts，asimpletrenchinwhichthefilamentliescoveredup。Asforthisfilament，itiseasilyextractedfromitssheathandreleaseddowntoitsbase，undertheshieldformedbythescale。
Seenunderthemagnifying-glass，itisaround，stiff，hornythread，midwayinthicknessbetweenahumanhairandahorse-hair。Itstipisalittlerough，pointedandbevelledtosomelengthdown。Themicroscopebecomesnecessaryifwewouldseeitsrealstructure，whichismuchlesssimplethanitatfirstappears。Weperceivethatthebevelledend-partconsistsofaseriesoftruncatedcones，fittingoneintotheother，withtheirwidebaseslightlyprojecting。Thisarrangementproducesasortoffile，asortofraspwithverymuchbluntedteeth。Whenpressedontheslide，thethreaddividesintofourpiecesofunequallength。Thetwolongerendinthetoothedbevel。
Theycometogetherinaverynarrowgroove，whichreceivesthetwoother，rathershorterpieces。Thesebothendinapoint，which，however，isnottoothedanddoesnotprojectasfarasthefinalrasp。
Theyalsounitetoformagroove，whichfitsintothegrooveoftheothertwo，thewholeconstitutingacompletechannelorduct。
Moreover，thetwoshorterpieces，consideredtogether，canmove，lengthwise，inthegroovethatreceivesthem；theycanalsomoveoneovertheother，alwayslengthwise，somuchsothat，ontheslideofthemicroscope，theirterminalpointsareseldomsituatedonthesamelevel。
Ifwithourscissorswecutapieceoftheinoculating-threadfromthelivinginsectandexaminethesectionunderthemagnifying-glass，weshallseetheinnergroovelengthenoutandprojectbeyondtheoutergrooveandthengoinagaininturn，whilefromthewoundthereoozesatinyalbimunousdrop，doubtlessproceedingfromtheliquidthatgivestheeggthesingularappendagetowhichweshallcomepresently。
Bymeansoftheselongitudinalmovementsoftheinnertrenchinsidetheoutertrenchandofthesliding，oneovertheother，ofthetwoportionsoftheformer，theeggcanbedespatchedtotheendoftheovipositornotwithstandingtheabsenceofanymuscularcontraction，whichisimpossibleinahornyconduit。
Wehaveonlytopresstheuppersurfaceoftheabdomentoseeitdisjointitselffromthefirstsegment，asthoughtheinsecthadbeencutalmostintwoatthatpoint。Awidegaporhiatusappearsbetweenthefirstandsecondrings；and，underathinmembrane，thebaseoftheovipositorbulgesout，bentbackintoastouthook。Herethefilamentpassesthroughtheinsectfromendtoendandemergesunderneath。Itsissueisthereforenearthebaseoftheabdomen，insteadofatthetip，asusual。Thiscuriousarrangementhastheeffectofshorteningthelever-armoftheovipositorandbringingthestarting-pointofthefilamentnearertothefulcrum，namely，thelegsoftheinsect，andofthusassistingthedifficulttaskofinoculationbymakingthemostoftheeffortexpended。
Tosumup，theovipositorwhenatrestgoesroundtheabdomen。
Startingatthebase，onthelowersurface，itrunsroundthebellyfromfronttobackandthenreturnsfrombacktofrontontheuppersurface，whereitendsatalmostthesamelevelasitsstarting-point。
Itslengthis14millimetres。（。546inch——Translator’sNote。）ThisfixesthelimitofthedepthwhichtheprobeisabletoreachintheMason-bee’snests。
OnelastwordontheLeucopsis’weapon。Inthedyinginsect，beheaded，strippedoflegsandwings，withapinstuckthroughitsbody，thesidesofthefissurecontainingtheinoculating-threadquiverviolently，asifthebellyweregoingtoopen，divideintwoalongthemedianlineandthenreuniteitstwohalves。Thethreaditselfgivesconvulsivetremblings；itcomesoutofitsscabbard，goesbackandslipsoutagain。Itisasthoughthelaying-implementcouldnotpersuadeitselftodiebeforeaccomplishingitsmission。Theinsect’ssupremeaimistheegg；and，solongastheleastsparkofliferemains，itmakesdyingeffortstolay。
LeucopsisgigasexploitsthenestsoftheMason-beeofthePebblesandtheMason-beeoftheShedswithequalzest。Toobservetheinsertionoftheeggatmyeaseandtowatchtheoperatoratworkoverandoveragain，Igavethepreferencetothelast-namedMason，whosenests，removedfromtheneighbouringroofsbymyorders，havehungforsomeyearsinthearchofmybasement。Theseclayhivesfastenedtotilessupplymewithfreshrecordseachsummer。IammuchindebtedtotheminthematteroftheLeucopsis’life-history。
Bywayofcomparisonwithwhattookplaceundermyroof，Iusedtoobservethesamescenesonthepebblesofthesurroundingwastelands。
Myexcursions，alas，didnotallrewardmyzeal，whichzealwasnotwithoutmeritinthemercilesssunshine；butstill，atrareintervals，IsucceededinseeingsomeLeucopsisdiggingherprobeintothemortardome。Lyingflatontheground，fromthebeginningtotheendoftheoperation，whichsometimeslastedforhours，Icloselywatchedtheinsectinitseverymovement，whilemyDog，wearyofbeingoutofdoorsinthatscorchingheat，woulddiscreetlyretirefromthefrayand，withhistailbetweenhislegsandhistonguehangingout，gohomeandstretchhimselfatfulllengthonthecooltilesofthehall。
Howwisehewastoscornthispebble-gazing！Iwouldcomeinhalf-
roasted，asbrownasaberry，tofindmyfriendBullwedgedintoacorner，hisbacktothewall，sprawlingonallfours，while，withheavingsides，hepantedforththelastspraysofsteamfromhisoverheatedinterior。Yes，hewasmuchbetter-advisedtoreturnasfastashecouldtotheshadeofthehouse。Whydoesmanwanttoknowthings？Whyishenotindifferenttothem，withtheloftyphilosophyoftheanimals？Whatinterestcananythinghaveforusthatdoesnotfillourstomachs？Whatistheuseoflearning？Whatistheuseoftruth，whenprofitisallthatmatters？WhyamI——thedescendant，sotheytellme，ofsometertiaryBaboon——afflictedwiththepassionforknowledgefromwhichBull，myfriendandcompanion，isexempt？
Why……oh，wherehaveIgotto？Iwasgoingin，wasn’tI，withasplittingheadache？Quick，letusgetbacktooursubject！
ItwasinthefirstweekofJulythatIsawtheinoculationbeginonmyChalicodomasiculanests。Theparasiteisathertaskinthehottestpartoftheday，closeonthreeo’clockintheafternoon；andworkgoesonalmosttotheendofthemonth，decreasinggraduallyinactivity。IcountasmanyastwelveLeucopsesatatimeonthemostthickly-populatedpairoftiles。Theinsectslowlyandawkwardlyexploresthenests。Itfeelsthesurfacewithitsantennae，whicharebentatarightangleafterthefirstjoint。Then，motionless，withloweredhead，itseemstomeditateandtodebatewithinitselfonthefitnessofthespot。Isithereorsomewhereelsethatthecovetedlarvalies？Thereisnothingoutside，absolutelynothing，totellus。
Itisastonyexpanse，bumpybutyetveryuniforminappearance，forthecellshavedisappearedunderalayerofplaster，aworkofpublicinteresttowhichthewholeswarmdevotesitslastdays。IfImyself，withmylongexperience，hadtodecideuponthesuitablepoint，evenifIwereatlibertytomakeuseofalensforexaminingthemortargrainbygrainandtoauscultatethesurfaceinordertogatherinformationfromthesoundemitted，Ishoulddeclinethejob，persuadedinadvancethatIshouldfailninetimesoutoftenandonlysucceedbychance。
Wheremydiscernment，aidedbyreasonandmyopticalcontrivances，fails，theinsect，guidedbythewandsofitsantennae，neverblunders。Itschoiceismade。Seeitunsheathingitslonginstrument。
Theprobepointsnormallytowardsthesurfaceandoccupiesnearlythecentralspotbetweenthetwomiddle-legs。Awidedislocationappearsontheback，betweenthefirstandsecondsegmentsoftheabdomen；andthebaseoftheinstrumentswellslikeabladderthroughthisopening；
whilethepointstrivestopenetratethehardclay。Theamountofenergyexpendedisshownbythewayinwhichthebladderquivers。Ateverymomentweexpecttoseethefrailmembraneburstwiththeviolenceoftheeffort。Butitdoesnotgiveway；andthewiregoesdeeperanddeeper。
Raisingitselfhighonitslegs，togivefreeplaytoitsapparatus，theinsectremainsmotionless，theonlysignofitsarduouslaboursbeingaslightvibration。Iseesomeperforatorswhohavefinishedoperatinginaquarterofanhour。Thesearethequickestatthebusiness。Theyhavebeenluckyenoughtocomeacrossawallwhichislessthickandlesshardthanusual。Iseeotherswhospendasmanyasthreehoursonasingleoperation，threelonghoursofpatientwatchingforme，inmyanxietytofollowthewholeperformancetotheend，threelonghoursofimmobilityfortheinsect，whichisevenmoreanxioustomakesureofboardandlodgingforitsegg。Butthenisitnotataskoftheutmostdifficultytointroduceahairintothethicknessofastone？Tous，withallthedexterityofourfingers，itwouldbeimpossible；totheinsect，whichsimplypusheswithitsbelly，itisjusthardwork。
Notwithstandingtheresistanceofthesubstancetraversed，theLeucopsisperseveres，certainofsucceeding；andshedoessucceed，althoughIamstillunabletounderstandhersuccess。Thematerialthroughwhichtheprobehastopenetrateisnotaporoussubstance；itishomogeneousandcompact，likeourhardenedcement。InvaindoI
directmyattentiontotheexactpointwheretheinstrumentisatwork；Iseenofissure，noopeningthatcanfacilitateaccess。A
miner’sdrillpenetratestherockonlybypulverizingit。Thismethodisnotadmissiblehere；theextremedelicacyoftheimplementisopposedtoit。Thefrailstemrequires，soitseemstome，aready-
madeway，acrevicethroughwhichitcanslip；butthiscreviceIhaveneverbeenabletodiscover。Whataboutadissolvingfluidwhichwouldsoftenthemortarunderthepointoftheovipositor？No，forIseenotatraceofhumidityaroundthepointwherethethreadisatwork。I
fallbackuponafissure，alackofcontinuitysomewhere，althoughmyexaminationfailstodiscoveranyontheMason-bee’snest。Iwasbetterservedinanothercase。Leucopsisdorsigera，FAB。，settleshereggsonthelarvaoftheDiademAnthidium，whosometimesmakeshernestinreed-stumps。Ihaverepeatedlyseenherinsertheraugerthroughaslightruptureinthesideofthereed。Asthewallwasdifferent，woodinthelattercaseandmortarintheformer，perhapsitwillbebesttolookuponthematterasamystery。
Mysedulousattendance，duringthebestpartofJuly，infrontofthetileshangingfromthewallsofthearch，allowedmetoreckontheinoculations。Eachtimethattheinsect，onfinishingtheoperation，removeditsprobe，Imarkedinpenciltheexactpointatwhichtheinstrumentwaswithdrawn；andIwrotedownthedatebesideit。ThisinformationwastobeutilizedwhentheLeucopsisfinishedherlabours。
Whentheperforatorsaregone，Iproceedwithmyexaminationofthenests，coveredwithmyhieroglyphics，thepencillednotes。Oneresult，onewhichIfullyexpected，compensatesmestraightwayforallmywearywaitings。Undereachspotmarkedinblack，undereachspotwhenceIsawtheovipositorwithdrawn，Ialwaysfindacell，withnotasingleexception。Andyetthereareintervalsofsolidstonebetweenthecells：thepartition-wallsalonewouldaccountforsome。Moreover，thecompartments，whichareveryirregularlydisposedbyaswarmoftoilerswhoallworkintheirownsweetway，havegreatirregularcavitiesbetweenthem，whichendbybeingfilledupwiththegeneralplasteringofthenest。Theresultofthisarrangementisthatthemassiveportionscoveralmostthesamespaceasthehollowportions。
Thereisnothingoutsidetoshowwhethertheunderlyingregionsarefullorempty。Itisquiteimpossibleformetodecideif，bydiggingstraightdown，Ishallcometoahollowcellortoasolidwall。
Buttheinsectmakesnomistake：theexcavationsundermypencil-marksbearwitnesstothat；italwaysdirectsitsapparatustowardsthehollowofacell。Howisitapprisedwhetherthepartbelowisemptyorfull？Itsorgansofinformationareundoubtedlytheantennae，whichfeeltheground。Theyaretwofingersofunparalleleddelicacy，whichpryintothebasementbytappingonthepartaboveit。Thenwhatdothosepuzzlingorgansperceive？Asmell？Notatall；IalwayshadmydoubtsofthatandnowIamcertainofthecontrary，afterwhatI
shalldescribeinamoment。Dotheyperceiveasound？Arewetotreatthemasasuperiorkindofmicrophone，capableofcollectingtheinfinitesimalechoesofwhatisfullandthereverberationsofwhatisempty？Itisanattractiveidea，butunfortunatelytheantennaeplaytheirpartequallywellonahostofoccasionswhentherearenovaultstoreverberate。Weknownothingandareperhapsdestinednevertoknowanythingoftherealvalueoftheantennalsense，towhichwehavenothinganalogous；but，thoughitisimpossibleforustosaywhatitdoesperceive，weareatleastabletorecognizetosomeextentwhatitdoesnotperceiveand，inparticular，todenyitthefacultyofsmell。
Asamatteroffact，Inotice，withextremesurprise，thatthegreatmajorityofthecellsvisitedbytheLeucopsis’probedonotcontaintheonethingwhichtheinsectisseeking，namely，theyounglarvaoftheMason-beeenclosedinitscocoon。TheircontentsconsistoftherefusesooftenmetwithinoldChalicodoma-nests：liquidhoneyleftunemployed，becausetheegghasperished；spoiltprovisions，sometimesmildewed，orsometimesatarrymass；adeadlarva，stiffenedintoabrowncylinder；theshrivelledcorpseofaperfectinsect，whichlackedthestrengthtoeffectitsdeliverance；dustandrubbishwhichhascomefromtheexit-windowafterwardsclosedupbytheoutercoatingofplaster。Theodoriferouseffluviathatcanemanatefromtheserelicscertainlypossessverydiversecharacters。Asenseofsmellwithanysubtletyatallwouldnotbedeceivedbythisstuff，sour，’high，’mustyortarryasthecasemaybe；eachcompartment，accordingtoitscontents，hasaspecialaroma，whichwemightormightnotbeabletoperceive；andthisaromamostcertainlybearsnoresemblancetothatwhichwemayassumethemuch-desiredfreshlarvatopossess。IfneverthelesstheLeucopsisdoesnotdistinguishbetweenthesevariouscellsanddrivestheprobeintoallofthemindifferently，isthisnotanevidentproofthatsmellisnoguidewhatevertoherinhersearch？Otherconsiderations，whenIwastreatingoftheHairyAmmophila，enabledmetoassertthattheantennaehavenoolfactorypowers。To-day，thefrequentmistakesoftheLeucopsis，whoseantennaeareneverthelessconstantlyexploringthesurface，makethisconclusionabsolutelycertain。
Theperforatorofclaynestshas，soitseemstome，deliveredusfromanoldphysiologicalfallacy。Shewoulddeservestudying，iffornootherresultthanthis；butherinterestisfarfrombeingexhausted。
Letuslookatherfromanotherpointofview，whosefullimportancewillnotbeapparentuntiltheend；letusspeakofsomethingwhichI
wasveryfarfromsuspectingwhenIwassoassiduouslywatchingthenestsofmyMason-bees。
ThesamecellcanreceivetheLeucopsis’probeanumberoftimes，atintervalsofseveraldays。IhavesaidhowIusedtomarkinblacktheexactplaceatwhichthelaying-implementhadenteredandhowIwrotethedateoftheoperationbesideit。Well，atmanyofthesealreadyvisitedspots，concerningwhichIpossessedthemostauthenticdocuments，Isawtheinsectreturnasecond，athirdandevenafourthtime，eitheronthesamedayorsomewhileafter，anddriveitsinoculating-threadinagain，atpreciselythesameplace，asthoughnothinghadhappened。Wasitthesameindividualrepeatingheroperationinacellwhichshehadvisitedbeforebutforgotten，ordifferentindividualscomingoneaftertheothertolayanegginacompartmentthoughttobeunoccupied？Icannotsay，havingneglectedtomarktheoperators，forfearofdisturbingthem。
Asthereisnothing，exceptthemarkofmypencil，amarkdevoidofmeaningtotheinsect，toindicatethattheaugerhasalreadybeenatworkthere，itmayeasilyhappenthatthesameoperator，findingunderherfeetaspotalreadyexploitedbyherselfbuteffacedfromhermemory，repeatsthethrustofhertoolinacompartmentwhichshebelievesherselftobediscoveringforthefirsttime。Howeverretentiveitsmemoryforplacesmaybe，wecannotadmitthattheinsectremembersforweeksonend，aswellaspointbypoint，thetopographyofanestcoveringasurfaceofsomesquareyards。Itsrecollections，ifithaveany，serveitbadly；theoutwardappearancegivesitnoinformation；anditsdrillenterswhereveritmayhappentodiscoveracell，atpointsthathavealreadyperhapsbeenpiercedseveraltimesover。
Itmayalsohappen——andthisappearstomethemostfrequentcase——
thatoneexploiterofacellissucceededbyasecond，athird，afourthandothersstill，allfiredwiththenewcomer’szealbecausetheirpredecessorshaveleftnotraceoftheirpassage。Inonewayoranother，thesamecellisexposedtomanifoldlayings，thoughitscontents，theChalicodoma-grub，beonlythebarerationofasingleLeucopsis-grub。
Thesereiteratedboringsarenotatallrare：Inotedascoreofthemonmytiles；and，inthecaseofsomecells，theoperationwasrepeatedbeforemyeyesasoftenasfourtimes。Nothingtellsusthatthisnumberwasnotexceededinmyabsence。ThelittlethatIobservedpreventsmefromfixinganylimit。Andnowamomentousquestionarises：istheeggreallylaideachtimethattheprobeentersacell？
Icanseenottheslightestexcuseforsupposingthecontrary。Theovipositor，becauseofitshornynature，canhavebutaverydullsenseoftouch。Theinsectisapprisedofthecontentsofthecellonlybytheendofthatlonghorse-hair，anotverytrustworthywitness，Ishouldimagine。Theabsenceofresistancetellsitthatithasreachedanemptyspace；andthisisprobablytheonlyinformationthattheinsensibleimplementcansupply。Thedrillboringthroughtherockcannottellthemineranythingaboutthecontentsofthecavernwhichithasentered；andthecasemustbethesamewiththerigidfilamentoftheLeucopses。
Nowthatthethreadhasreacheditsgoal，whatdoesthecellcontain？
Mildewedhoney，dustandrubbish，ashrivelledlarva，oralarvaingoodcondition？Aboveall，doesitalreadycontainanegg？Thislastquestioncallsforadefiniteanswer，butasamatteroffactitisimpossiblefortheinsecttolearnanythingfromahorse-haironthatmostdelicatematter，thepresenceorabsenceofanegg，amereatomofathing，inthatvastapartment。Evenadmittingsomesenseoftouchattheendofthedrill，oneinsuperabledifficultywouldalwaysremain：thatoffindingtheexactspotwherethetinyspeckliesinthosespaciousandmysteriousregions。Igosofarastobelievethattheovipositortellstheinsectnothing，oratanyrateverylittle，oftheinsideofthecell，whetherpropitiousornottothedevelopmentofthegerm。Perhapseachthrustoftheinstrument，providedthatitmeetswithnoresistancefromsolidmatter，laystheegg，towhoselottherefallsatonetimegood，wholesomefood，atanothermererefuse。
Theseanomaliescallformoreconclusiveproofsthantheroughdeductionsdrawnfromthenatureofthehornyovipositor。WemustascertaininadirectfashionwhetherthecellintowhichtheaugerhasbeendrivenseveraltimesoveractuallycontainsseveraloccupantsinadditiontothelarvaoftheMason-bee。WhentheLeucopseshadfinishedtheirborings，Iwaitedafewdayslongersoastogivetheyounggrubstimetodevelopalittle，whichwouldmakemyexaminationeasier。Ithenmovedthetilestothetableinmystudy，inordertoinvestigatetheirsecretswiththemostscrupulouscare。AndheresuchadisappointmentasIhaverarelyknownawaitedme。ThecellswhichI
hadseen，actuallyseen，withmyowneyes，piercedbytheprobetwoorthreeorevenfourtimes，containedbutoneLeucopsis-grub，onealone，eatingawayatitsChalicodoma。Others，whichhadalsobeenrepeatedlyprobed，containedspoiltremnants，butneveraLeucopsis。Oholypatience，givemethecouragetobeginagain！Dispelthedarknessanddelivermefromdoubt！
Ibeginagain。TheLeucopsis-grubisfamiliartome；Icanrecognizeit，withoutthepossibilityofamistake，inthenestsofboththeChalicodomaofthePebblesandtheChalicodomaoftheSheds。Allthroughthewinter，Irushabout，gettingmynestsfromtheroofsofoldshedsandthepebblesofthewaste-lands；Istuffmypocketswiththem，fillmybox，loadFavier’sknapsack；Icollectenoughtolitterallthetablesinmystudy；and，whenitistoocoldoutofdoors，whenthebitingmistralblows，Itearopenthefinesilkofthecocoonstodiscovertheinhabitant。MostofthemcontaintheMasonintheperfectstate；othersgivemethelarvaoftheAnthrax；others——
verynumerous，these——givemethelarvaoftheLeucopsis。Andthislastisalone，alwaysalone，invariablyalone。Thewholethingisutterlyincomprehensiblewhenoneknows，asIknow，howmanytimestheprobeenteredthosecells。
Myperplexityonlyincreaseswhen，onthereturnofsummer，IwitnessforthesecondtimetheLeucopsis’repeatedoperationsonthesamecellsandforthesecondtimefindasinglelarvainthecompartmentswhichhavebeenboredseveraltimesover。ShallIthenbeforcedtoacceptthattheaugerisabletorecognizethecellsalreadycontaininganeggandthatitthenceforthrefrainsfromlayingthere？
MustIadmitanextraordinarysenseoftouchinthatbitofhorse-
hair，orevenbetter，asortofdivinationwhichdeclareswheretheegglieswithouthavingtotouchit？ButIamraving！Thereiscertainlysomethingthatescapesme；andtheobscurityoftheproblemissimplyduetomyincompleteinformation。Opatience，supremevirtueoftheobserver，cometomyaidoncemore！Imustbeginalloveragainforthethirdtime。
Untilnow，myinvestigationshavebeenmadesometimeafterthelaying，ataperiodwhenthelarvaisatleastfairlydeveloped。Whoknows？Somethingperhapshappens，attheverycommencementofinfancy，thatmaymisleadmeafterwards。ImustapplytotheeggitselfifI
wouldlearnthesecretwhichthegrubwillnotreveal。IthereforeresumemyobservationsinthefirstfortnightofJuly，whentheLeucopsesarebeginningtovisitbusilybothMason-bee’snests。Thepebblesinthewaste-landssupplymewithplentyofbuildingsoftheChalicodomaoftheWalls；thebyresscatteredhereandthereinthefieldsgiveme，undertheirdilapidatedroofs，infragmentsbrokenoffwiththechisel，theedificesoftheChalicodomaoftheSheds。Iamanxiousnottocompletethedestructionofmyhomehives，alreadysosorelytriedbymyexperiments；theyhavetaughtmemuchandcanteachmemore。Aliencolonies，pickedupmoreorlesseverywhere，providemewithmybooty。Withmylensinonehandandmyforcepsintheother，I
gothroughmycollectiononthesameday，withtheprudenceandcarewhichonlythelaboratory-tablepermits。Theresultsatfirstfallfarshortofmyexpectations。IseenothingthatIhavenotseenbefore。I
makefreshexpeditions，afterafewdays’interval；Ibringbackfreshloadsoflumpsofmortar，untilatlastfortunesmilesuponme。
Reasonwasnotatfault。Eachthrustmeansthelayingofaneggwhentheprobereachesthecell。HereisacocoonoftheMason-beeofthePebbleswithaneggsidebysidewiththeChalicodoma-grub。Butwhatacuriousegg！Neverhavemyeyesbeheldthelike；andthenisitreallytheeggoftheLeucopsis？Greatwasmyapprehension。ButIbreathedagainwhenIfound，acoupleofweekslater，thattheegghadbecomethelarvawithwhichIwasfamiliar。ThosecocoonswithasingleeggareasnumerousasIcanwish；theyexceedmywishes：mylittleglassreceptaclesaretoofewtoholdthem。
Andhereareothers，morepreciousonesstill，withmanifoldlayings。
Ifindplentywithtwoeggs；Ifindsomewiththreeorfour；thebest-
colonisedoffermeasmanyasfive。And，tocrownmydelight，thejoyoftheseekertowhomsuccesscomesatthelastmoment，whenheisonthevergeofdespair，hereagain，dulyfurnishedwithanegg，isasterilecocoon，thatistosay，onecontainingonlyashrivelledanddecayinglarva。Allmysuspicionsareconfirmed，downtothemostinconsequent：theegghousedwithamassofputrefaction。
ThenestsoftheMason-beeoftheWallsarethemoreregularinstructureandareeasiertoexamine，becausetheirbaseiswideopenonceitisseparatedfromthesupportingpebble；anditwasthesewhichsuppliedmewithbyfarthegreaterpartofmyinformation。
ThoseoftheMason-beeoftheShedshavetobechippedawaywithahammerbeforeonecaninspecttheircells，whichareheapedupanyhow；
andtheydonotlendthemselvesanythinglikesowelltodelicateinvestigations，astheysufferbothfromtheshockandtheill-
treatment。
Andnowthethingisdone：itremainscertainthattheLeucopsis’
layingisexposedtoveryexceptionaldangers。Shecanentrusttheeggtosterilecells，withoutprovisionsfittouse；shecanestablishseveralinthesamecell，thoughthiscellcontainsnourishmentforoneonly。Whethertheyproceedfromasingleindividualreturningseveraltimes，byinadvertence，tothesameplace，oraretheworkofdifferentindividualsunawareofthepreviousborings，thosemultiplelayingsareveryfrequent，almostasmuchsoasthenormallayings。
ThelargestwhichIhavenoticedconsistedoffiveeggs，butwehavenoauthorityforlookinguponthisnumberasanoutsidelimit。Whocouldsay，whentheperforatorsarenumerous，towhatlengthsthisaccumulationcango？Iwillsetforthonsomefutureoccasionhowtherationofoneeggremainsinrealitytherationofoneegg，despitethemultiplicityofbanqueters。
Iwillendbydescribingtheegg，whichisawhite，opaqueobject，shapedlikeamuch-elongatedoval。Oneoftheendsislengthenedoutintoaneckorpedicle，whichisaslongastheeggproper。Thisneckissomewhatwrinkled，sinuousandasaruleconsiderablycurved。Thewholethingisnotatallunlikecertaingourdswithanelongatedpaunchandasnake-likeneck。Thetotallength，pedicleandall，isabout3millimetres。（Aboutone-eighthofaninch。——Translator’sNote。）Itisneedlesstosay，afterrecognizingthegrub’smanneroffeeding，thatthiseggisnotlaidinsidethefosteringlarva。Yet，beforeIknewthehabitsoftheLeucopsis，IwouldreadilyhavebelievedthateveryHymenopteronarmedwithalongprobeinsertshereggsintothevictim’ssides，astheIchneumon-fliesdototheCaterpillars。Imentionthisforthebenefitofanywhomaybeunderthesameerroneousimpression。
TheLeucopsis’eggisnotevenlaidupontheMason-bee’slarva；itishungbyitsbentpedicletothefibrouswallofthecocoon。WhenIgotoworkverydelicately，soasnottodisturbthearrangementinknockingthenestoffitssupport，andthenextractandopenthecocoon，Iseetheeggswingingfromthesilkenvault。Butittakesverylittletomakeitfall。Andso，mostoften，eventhoughitbemerelytheeffectoftheshocksustainedwhenthenestisremovedfromitspebble，Ifindtheeggdetachedfromitssuspension-pointandlyingbesidethelarva，towhichitneveradheresinanycircumstances。TheLeucopsis’probedoesnotpenetratebeyondthecocoontraversed；andtheeggremainsfastenedtotheceiling，inthecrookofsomesilkythread，bymeansofitshookedpedicle。
INDEX。
AmazonAnt（seeRedAnt）。
Ammophila。
Ammophilahirsuta（seeHairyAmmophila）。
Ant（seealsoBlackAnt，RedAnt）。
Anthidium（seealsoCotton-bee，DiademAnthidium）。
Anthophora（seealsoHairy-footedAnthophora）。
Anthrax（seealsoAnthraxsinuata）。
Anthraxsinuata。
Anthrenus。
Ape。
Aphis。
Baboon。
Bastien。
Bee。
Bembex（seealsoBembexrostrata）。
Bembexrostrata。
BlackAnt。
Blanchard，Emile。
BlueOsmia。
Bombylius。
Bumble-bee。
Butterfly。
Cabbage-caterpillar。
Cagliostro。
Carrier-pigeon。
CastelnaudelaPorte，FrancisComtede。
Cat。
Caterpillar（seealsoCabbage-caterpillar，GreyWorm，ProcessionaryCaterpillar，Spurge-caterpillar）。
Cerceris（seealsoGreatCerceris）。
Cerceristuberculata（seeGreatCerceris）。
Cetonia。
Chalcis。
Chalicodoma（seeMason-bee）。
Chalicodomamuraria（seeMason-beeoftheWalls）。
Chalicodomapyrenaica，C。pyrrhopeza，C。rufitarsis，C。sicula（seeMason-beeoftheSheds）。
Chalicodomarufescens（seeMason-beeoftheShrubs）。
Chat。
Chrysis（seealsoParnopescarnea，Stilbumcalens）。
Clerus。
Coelyoxis。
CommonLizard。
CommonWasp。
CorneliusNepos。
Cotton-bee。
Cricket。
Crioceris。
Crocisa。
Darwin，CharlesRobert。
Darwin，Erasmus。
DiademAnthidium。
Dioxys。
Dioxyscincta（seeDioxys）。
Dog。
Dufour，JeanMarieLeon。
DuhamelduMonceau，HenriLouis。
Duruy，JeanVictor。
Euclid。
EumenesAmadei。
EyedLizard。
Fabre，Mlle。Aglae，theauthor’sdaughter。
Fabre，Mlle。Antonia，theauthor’sdaughter。
Fabre，Mlle。Claire，theauthor’sdaughter。
Fabre，Mlle。Lucie，theauthor’sgranddaughter。
Favier，theauthor’sfactotum。
Fly。
Franklin，Benjamin。
Gad-fly。
Gnat。
GoldenWasp（seeChrysis）。
Gold-fish。
Grasshopper（seeGreenGrasshopper）。
GreatCerceris。
GreenGrasshopper。
GreyLizard。
GreyWorm。
HairyAmmophila。
Hairy-footedAnthophora。
Halictus。
Hive-bee。
Huber，Francois。
Ichneumon-fly。
Lacordaire，JeanTheodore。
Lamb。
Lark。
Latreille’sOsmia。
Leaf-cutter（seeMegachile）。
Leucopsis。
Leucopsisdorsigera。
Leucopsisgigas（seeLeucopsis）。
LeVaillant，Francois。
Lion。
Lizard（seeCommonLizard，EyedLizard，GreyLizard）。
Locust。
Loriol，Dr。
Loriol，Mme。
Lucas，PierreHippolyte。
MacmillanandCo。，Ltd。
"MademoiselleMori"，authorof。
Mantis（seePrayingMantis）。
Martin。
Mason-bee（seealsothevarietiesbelow）。
Mason-beeofthePebbles（seeMason-beeoftheWalls）。
Mason-beeoftheSheds。
Mason-beeoftheShrubs。
Mason-beeoftheWalls。
Megachile。
Megachileapicalis（seeMegachile）。
Melecta。
Meloe（seeOil-beetle）。
Mesmer。
Miall，Bernard。
Monodontomeruscupreus。
Morawitz’Osmia。
Moth。
Mutilla。
NapoleonIII。，theEmperor。
Newton，SirIsaac。
Oil-beetle。
Oryctes。
Osmia（seealsothevarietiesbelow）。
Osmiacyanea（seeBlueOsmia）。
Osmiacyanoxantha。
OsmiaLatreillii（seeLatreille’sOsmia）。
OsmiaMorawitzi（seeMorawitz’Osmia）。
Osmiatricornis（seeThree-hornedOsmia）。
Osmiatridentata（seeThree-prongedOsmia）。
Ox。
Parnopescarnea。
Perez，ProfessorJean。
Philanthusapivorus。
Polyergusrufescens（seeRedAnt）。
Pompilus。
PrayingMantis。
ProcessionaryCaterpillar。
Psithyrus。
Ptinus。
Rabbit。
Reaumur，ReneAntoineFerchaultde。
RedAnt。
Republican（seeSocialWeaver-bird）。
Resin-bee。
Rhinoceros-beetle（seeOryctes）。
RingedCalicurgus（seePompilus）。
Rodwell，MissFrances。
Rose-chafer（seeCetonia）。
SacredBeetle。
Sapygapunctata（seeSpottedSapyga）。
Saw-fly。
Scolia。
Sheep。
SicilianMason-bee（seeMason-beeoftheSheds）。
SocialBee（seeHive-bee）。
SocialWasp（seeCommonWasp）。
SocialWeaver-bird。
Sphex（seealsoYellow-wingedSphex。）
Spider。
SpottedSapyga。
Spurge-caterpillar。
Stelis（seealsoStelisnasuta）。
Stelisnasuta。
Stilbumcalens。
Swallow。
Swift。
Tachina。
Tachytes。
TeixeiradeMattos，Alexander。
Three-hornedOsmia。
Three-prongedOsmia。
Tiger。
Toussenel，Alphonse。
Tripoxylon。
Turnip-caterpillar，Turnip-moth（seeGreyWorm）。
Wagtail（seeWhiteWagtail）。
WartedCerceris（seeGreatCerceris）。
Wasp（seealsoCommonWasp）。
Weevil。
WhiteWagtail。
WildBoar。
Wolf。
Yellow-wingedSphex。