CHAPTERXTHEGREYFLESHFLIES
Herethecostumechanges，notthemanneroflife。Wefindthesamefrequentingofdeadbodies，thesamecapacityforthespeedyliquefactionofthefleshymatter。Iamspeakingofanash—grayfly，thegreenbottle’ssuperiorinsize，withbrownstreaksonherbackandsilvergleamsonherabdomen。Notealsotheblood—redeyes，withthehardlookoftheknackerinthem。ThelanguageofscienceknowsherasSarcophaga，theflesheater;inthevulgartonguesheisthegreyfleshfly，orsimplythefleshfly。
Letnottheseexpressions，howeveraccurate，misleadusintobelievingforamomentthattheSarcophagaearetheboldcompanyofmastertainterswhohauntourdwellings，moreparticularlyinautumn，andplanttheirvermininourill—guardedviands。TheauthorofthoseoffencesisCalliphoravomitoria，thebluebottle，whoisofastouterbuildandarrayedindarkestblue。Itisshewhobuzzesagainstourwindowpanes，whocraftilybesiegesthemeatsafeandwholiesinwaitinthedarknessforanopportunitytooutwitourvigilance。Theother，thegreyfly，worksjointlywiththegreenbottles，whodonotventureinsideourhousesandwhoworkinthesunlight。Lesstimid，however，thanthey，shouldtheoutdooryieldbesmall，shewillsometimescomeindoorstoperpetratehervillainies。Whenherbusinessisdone，shemakesoffasfastasshecan，forshedoesnotfeelathomewithus。
Atthismoment，mystudy，averymodestextensionofmyopenairestablishments，hasbecomesomethingofacharnelhouse。Thegreyflypaysmeavisit。IfIlayapieceofbutcher’smeatonthewindowsill，shehastensup，worksherwillonitandretires。Nohidingplaceescapeshernoticeamongthejars，cups，glassesandreceptaclesofeverykindwithwhichmyshelvesarecrowded。
Withaviewtocertainexperiments，Icollectedaheapofwaspgrubs，asphyxiatedintheirundergroundnests。Stealthilyshearrives，discoversthefatpileand，hailingastreasuretrovethisprovenderwhereofherraceperhapshasnevermadeusebefore，entruststoitaninstallmentofherfamily。Ihaveleftatthebottomofaglassthebestpartofahard—boiledeggfromwhichI
havetakenafewbitsofwhiteintendedforthegreenbottlemaggots。Thegreyflytakespossessionoftheremains，recksnotoftheirnoveltyandcolonizesthem。Everythingsuitsherthatfallswithinthecategoryofalbuminousmatters:everything，downtodeadsilkworms;everything，downtoamessofkidney—beansandchick—peas。
Nevertheless，herpreferenceisforthecorpse:furredbeastandfeatheredbeast，reptileandfish，indifferently。Togetherwiththegreenbottles，sheissedulousinherattendanceonmypans。
Dailyshevisitsmysnakes，takesnoteoftheconditionofeachofthem，savorsthemwithherproboscis，goesaway，comesback，takeshertimeandatlastproceedstobusiness。Still，itisnothere，amidthetumultofcallers，thatIproposetofollowheroperations。Alumpofbutcher’smeatlaidonthewindowsill，infrontofmywritingtable，willbelessoffensivetotheeyeandwillfacilitatemyobservations。
TwofliesofthegenusSarcophagafrequentmyslaughteryard:
SarcophagacarnariaandSarcophagahaemorrhoidalis，whoseabdomenendsinaredspeck。Thefirstspecies，whichisalittlelargerthanthesecond，ismorenumerousanddoesthebestpartoftheworkintheopenairshamblesofthepans。Itisthisflyalsowho，atintervalsandnearlyalwaysalone，hastenstothebaitexposedonthewindowsill。
Shecomesupsuddenly，timidly。SoonshecalmsherselfandnolongerthinksoffleeingwhenIdrawnear，forthedishsuitsher。
Sheissurprisinglyquickaboutherwork。Twiceover——buzz！Buzz！—
—thetipofherabdomentouchesthemeat;andthethingisdone:agroupofverminwrigglesout，releasesitselfanddispersessonimblythatIhavenotimetotakemylensandcountthenaccurately。Asseenbythenakedeye，therewereadozenofthem。
Whathasbecomeofthem？Onewouldthinkthattheyhadgoneintotheflesh，attheveryspotwheretheywerelaid，soquicklyhavetheydisappeared。Butthatdiveintoasubstanceofsomeconsistencyisimpossibletothesenewbornweaklings。Wherearethey？Ifindthemmoreorlesseverywhereinthecreasesofthemeat;singlyandalreadygropingwiththeirmouths。Tocollecttheminordertonumberthemisnotpracticable，forIdonotwanttodamagethem。Letusbesatisfiedwiththeestimatemadeatarapidglance:thereareadozenorso，broughtintotheworldinonedischargeofalmostinappreciablelength。
Thoselivegrubs，takingtheplaceoftheusualeggs，havelongbeenknown。Everybodyisawarethatthefleshfliesbringforthlivingmaggots，insteadoflayingeggs。Theyhavesomuchtodoandtheirworkissourgent！Tothem，theinstrumentsofthetransformationofdeadmatter，adaymeansaday，alongspaceoftimewhichitisallimportanttoutilize。Thegreenbottle’seggs，thoughtheseareofveryrapiddevelopment，taketwenty—fourhourstoyieldtheirgrubs。Thefleshfliessaveallthistime。Fromtheirmatrix，laborersflowstraightwayandsettoworkthemomenttheyareborn。Withtheseardentpioneersofsanitation，thereisnorestattendantuponthehatching，thereisnotaminutelost。
Thegang，itistrue，isnotanumerousone;buthowoftencanitnotberenewed！ReadReaumur’sdescriptionofthewonderfulprocreatingmachineryboastedbytheFleshflies。Itisaspiralribbon，avelvetyscrollwhosenapisasortoffleeceofmaggotssetcloselytogetherandeachcasedinasheath。Thepatientbiographercountedthehost:itnumbers，hetellsus，nearlytwentythousand。Youareseizedwithstupefactionatthisanatomicalfact。
Howdoesthegrayflyfindthetimetosettleafamilyofsuchdimensions，especiallyinsmallpackets，asshehasjustdoneonmywindowsill？Whatanumberofdeaddogs，molesandsnakesmustshenotvisitbeforeexhaustingherwomb！Willshefindthem？Corpsesofmuchsizedonotaboundtothatextentinthecountry。Aseverythingsuitsher，shewillalightonotherremainsofminorimportance。Shouldtheprizebearichone，shewillreturntoittomorrow，thedayafterandlaterstill，overandoveragain。Inthecourseoftheseason，bydintofpacketsofgrubsdepositedhere，thereandeverywhere，shewillperhapsendbyhousingherentirebrood。Butthen，ifallthingsprosper，whataglut，forthereareseveralfamiliesbornduringtheyear！Wefeelitinstinctively:theremustbeachecktothesegenerativeenormities。
Letusfirstconsiderthegrub。Itisasturdymaggot，easytodistinguishfromthegreenbottle’sbyitslargergirthandespeciallybythewayinwhichitsbodyterminatesbehind。Thereishereasuddenbreakingoff，hollowedintoadeepcup。Atthebottomofthiscrateraretwobreathingholes，twostigmatawithamber—redtips。Theedgeofthecavityisfringedwithhalfascoreofpointed，fleshyfestoons，whichdivergelikethespikesofacoronet。Thecreaturecancloseoropenthisdiadematwillbybringingthedenticulationstogetherorbyspreadingthemoutwide。
Thisprotectstheairholeswhichmightotherwisebechokedupwhenthemaggotdisappearsintheseaofbroth。Asphyxiawouldsupervene，ifthetwobreathingholesatthebackbecameobstructed。Duringtheimmersion，thefestoonedcoronetshutslikeaflowerclosingitspetalsandtheliquidisnotadmittedtothecavity。
Nextfollowstheemergence。Thehindpartreappearsintheair，butappearsalone，justatthelevelofthefluid。Thenthecoronetspreadsoutafresh，thecupgapesandassumestheaspectofatinyflower，withthewhitedenticulationsforpetalsandthetwobrightreddots，thestigmataatthebottom，forstamens。Whenthegrubs，pressedoneagainsttheother，withtheirheadsdownwardsinthefetidsoup，makeanunbrokenshoal，thesightofthosebreathingcupsincessantlyopeningandclosing，withalittleclacklikeavalve，almostmakesoneforgetthehorrorsofthecharnelyard。ItsuggestsacarpetoftinySeaanemones。Themaggothasitsbeautiesafterall。
Itisobvious，iftherebeanylogicinthings，thatagrubsowell—protectedagainstasphyxiationbydrowningmustfrequentliquidsurroundings。Onedoesnotencircleone’shindquarterswithacoronetforthesolesatisfactionofdisplayingit。Withitsapparatusofspokes，theGreyFly’sgrubinformsusofthedangerousnatureofitsfunctions:whenworkinguponacorpse，itrunstheriskofdrowning。Howisthat？Rememberthegrubsofthegreenbottle，fedonhard—boiledwhiteofegg。Thedishsuitsthem;
only，bytheactionoftheirpepsin，itbecomessofluidthattheydiesubmerged。Becauseoftheirhinderstigmata，whichareactuallyontheskinanddevoidofanydefensivemachinery，theyperishwhentheyfindnosupportapartfromtheliquid。
Thefleshfly’smaggots，thoughincomparableliquefiers，knownothingofthisperil，eveninapuddleofcarrionbroth。Theirbulkyhindpartservesasafloatandkeepstheairholesabovethesurface。When，forfurtherinvestigation，theymustneedsgoundercompletely，theanemoneatthebackshutsandprotectsthestigmata。Thegrubsofthegrayflyareendowedwithalifebuoybecausetheyarefirstclassliquefiers，readytoincurthedangerofaduckingatanymoment。
WhenhighanddryonthesheetofcardboardwhereIplacethemtoobservethematmyease，theymoveaboutactively，withtheirbreathingrosewidespreadandtheirstigmatarisingandfallingasasupport。Thecardboardisonmytable，atthreestepsfromanopenwindow，andlitatthistimeofdayonlybythesoftlightofthesky。Well，themaggots，oneandallofthem，turnintheoppositedirectiontothewindow;theyhastily，madlytaketoflight。
Iturnthecardboardround，withouttouchingtherunaways。Thisactionmakesthecreaturesfacethelightagain。Forthwith，thetroopstops，hesitates，takesahalfturnandoncemoreretreatstowardsthedarkness。Beforetheendoftheracecourseisreached，Iagainturnthecardboard。Forthesecondtime，themaggotsveerroundandretracetheirsteps。RepeattheexperimentasoftenasI
will，eachtimethesquadwheelsaboutintheoppositedirectiontothewindowandpersistsinavoidingthetrapoftherevolvingcardboard。
Thetrackisonlyashortone:thecardboardmeasuresthreehand’sbreadthsinlength。Letusgivemorespace。Isettlethegrubsontheflooroftheroom;withahairpencil，Iturnthemwiththeirheadspointingtowardsthelightedaperture。Themomenttheyarefree，theyturnandrunfromthelight。Withallthespeedwhereoftheircripple’sshuffleallows，theycoverthetiledfloorofthestudyandgoandknocktheirheadsagainstthewall，twelvefeetoff，skirtingitafterwards，sometotherightandsometotheleft。Theyneverfeelfarenoughawayfromthathatefulilluminatedopening。
Whattheyareescapingfromisevidentlythelight，for，ifImakeitdarkwithascreen，thetroopdoesnotchangeitsdirectionwhenIturnthecardboard。Itthenprogressesquitereadilytowardsthewindow;but，whenIremovethescreen，itturnstailatonce。
Thatagrubdestinedtoliveinthedarkness，undertheshelterofacorpse，shouldavoidthelightisonlynatural;thestrangepartisitsveryperception。Themaggotisblind。Itspointedforepart，whichwehesitatetocallahead，bearsabsolutelynotraceofanyopticalapparatus;andthesamewitheveryotherpartofthebody。Thereisnothingbutonebare，smooth，whiteskin。Andthissightlesscreature，deprivedofanyspecialnervouspointsservedbyocularpower，isextremelysensitivetothelight。Itswholeskinisasortofretina，incapableofseeing，ofcourse，butable，atanyrate，todistinguishbetweenlightanddarkness。Underthedirectraysofasearchingsun，thegrub’sdistresscouldbeeasilyexplained。Weourselves;withourcoarseskin，incomparisonwiththatofthemaggot，candistinguishbetweensunshineandshadowwithoutthehelpoftheeyes。But，inthepresentcase，theproblembecomessingularlycomplicated。Thesubjectsofmyexperimentreceiveonlythediffusedlightofthesky，enteringmystudythroughanopenwindow;yetthistemperedlightfrightensthemoutoftheirsenses。Theyfleethepainfulapparition;theyarebentuponescapingatallcosts。
Nowwhatdothefugitivesfeel？Aretheyphysicallyhurtbythechemicalradiations？Aretheyexasperatedbyotherradiations，knownorunknown？Lightstillkeepsmanyasecrethiddenfromusandperhapsouropticalscience，bystudyingthemaggot，mightbecomethericherbysomevaluableinformation。Iwouldgladlyhavegonefartherintothequestion，hadIpossessedthenecessaryapparatus。ButIhavenot，IneverhavehadandofcourseInevershallhavetheresourceswhicharesousefultotheseeker。Thesearereservedforthecleverpeoplewhocaremoreforlucrativepoststhanforfairtruths。Letuscontinue，however，withinthemeasurewhichthepovertyofmymeanspermits。
Whendulyfattened，thegrubsofthefleshfliesgoundergroundtotransformthemselvesintopupae。Theburialisintended，obviously，togivethewormthetranquillitynecessaryforthemetamorphosis。Letusaddthatanotherobjectofthedescentistoavoidtheimportunitiesofthelight。Themaggotisolatesitselftothebestofitspowerandwithdrawsfromthegarishdaybeforecontractingintoalittlekeg。Inordinaryconditions，withaloosesoil，itgoeshardlylowerthanahand’sbreadthdown，forprovisionhastobemadeforthedifficultiesofthereturntothesurfacewhentheinsect，nowfullgrown，isimpededbyitsdelicateflywings。Thegrub，therefore，deemsitselfsuitablyisolatedatamoderatedepth。Sideways，thelayerthatshieldsitfromthelightisofindefinitethickness;upwards，itmeasuresaboutfourinches。Behindthisscreenreignsutterdarkness，theburiedone’sdelight。Thisiscapital。
Whatwouldhappenif，byanartifice，thesidewardlayerwerenowherethickenoughtosatisfythegrub？Now，thistime，Ihavethewherewithaltosolvetheproblem，intheshapeofabigglasstube，openatbothends，aboutthreefeetlongandlessthananinchwide。IuseittoblowtheflameofhydrogeninthelittlechemistrylessonswhichIgivemychildren。
Icloseoneendwithacorkandfillthetubewithfine，dry，siftedsand。Onthesurfaceofthislongcolumn，suspendedperpendicularlyinacornerofmystudy，IinstallsometwentySarcophagagrubs，feedingthemwithmeat。Asimilarpreparationisrepeatedinawiderjar，withamouthasbroadasone’shand。Whentheyarebigenough，thegrubsineitherapparatuswillgodowntothedepththatsuitsthem。Thereisnomoretobedonebuttoleavethemtotheirowndevices。
Thewormsatlastburythemselvesandhardenintopupae。Thisisthemomenttoconsultthetwoapparatus。ThejargivesmetheanswerwhichIshouldhaveobtainedintheopenfields。Fourinchesdown，orthereabouts，thewormshavefoundaquietlodging，protectedabovebythelayerthroughwhichtheyhavepassedandoneverysidebythethicknessofthevessel’scontents。Satisfiedwiththesite，theyhavestoppedthere。
Itisaverydifferentmatterinthetube。Theleastburiedofthepupaearehalfayarddown。Othersarelowerstill;mostofthemevenhavereachedthebottomofthetubeandaretouchingthecorkstopper，aninsuperablebarrier。Theselast，wecansee，wouldhavegoneyetdeeperiftheapparatushadallowedthem。Notoneofthescoreofgrubshassettledatthecustomaryhaltingplace;allhavetraveledfartherdownthecolumn，untiltheirstrengthgaveway。Intheiranxiousflight，theyhavedugdeeperandeverdeeper。
Whatweretheyflyingfrom？Thelight。Abovethem，thecolumntraversedformsamorethansufficientshelter;but，atthesides，theirksomesensationisstillfeltthroughacoatofearthhalfaninchthickifthedescentismadeperpendicularly。Toescapethedisturbingimpression，thegrubthereforegoesdeeperanddeeper，hopingtoobtainlowerdowntherestwhichisdenieditabove。Itonlyceasestomovewhenwornoutwiththeeffortorstoppedbyanobstacle。
Now，inasoftdiffusedlight，whatcanbetheradiationscapableofactinguponthisloverofdarkness？Theyarecertainlynotthesimpleluminousrays，forascreenoffine，heapedupearth，nearlyhalfaninchinthickness，isperfectlyopaque。Then，toalarmthegrub，towarnitoftheoverproximityoftheexteriorandsendittomaddepthsinsearchofisolation，otherradiations，knownorunknown，mustberequired，radiationscapableofpenetratingascreenagainstwhichordinaryradiationsarepowerless。Whoknowswhatvistasthenaturalphilosophyofthemaggotmightopenouttous？Forlackofapparatus，Iconfinemyselftosuspicions。
Togoundergroundtoayard’sdepth——andfartherifmytubehadallowedit——isonthepartoftheFleshfly’sgrubavagaryprovokedbyunkindexperiment:neverwoulditburyitselfsolowdown，iflefttoitsownwisdom。Ahand’sbreadththicknessisquiteenough，isevenagreatdealwhen，aftercompletingthetransformation，ithastoclimbbacktothesurface，alaboriousoperationabsolutelyresemblingthetaskofanentombedwellsinker。Itwillhavetofightagainstthesandthatslipsandgraduallyfillsupthesmallamountofemptyspaceobtained;itwillperhaps，withoutcrowbarorpickaxe，havetocutitselfagallerythroughsomethingtantamounttotufa，thatistosay，throughearthwhichashowerhasrenderedcompact。Forthedescent，thegrubhasitsfangs;fortheassent，theflyhasnothing。Onlythatmomentcomeintoexistence，sheisaweakling，withtissuesstilldevoidofanyfirmness。Howdoesshemanagetogetout？Weshallknowbywatchingafewpupaeplacedatthebottomofatest—tubefilledwithearth。ThemethodoftheFleshflieswillteachusthatofthegreenbottlesandtheotherFlies，allofwhommakeuseofthesamemeans。
Enclosedinherpupa，thenascentflybeginsbyburstingthelidofhercasketwithaherniawhichcomesbetweenhertwoeyesanddoublesortreblesthesizeofherhead。Thiscephalicblisterthrobs:itswellsandsubsidesbyturns，owingtothealternatefluxandrefluxoftheblood。Itislikethepistonofanhydraulicpressopeningandforcingbackthefrontpartofthekeg。
Theheadmakesitsappearance。Thehydrocephalousmonstercontinuestheplayofherforehead，whileherselfremainingstationary。Insidethepupa，adelicateworkisbeingperformed:
thecastingofthewhitenymphaltunic。Allthroughthisoperation，theherniaisstillprojecting。Theheadisnottheheadofafly，butaqueer，enormousmitre，spreadingatthebaseintotworedskullcaps，whicharetheeyes。Tosplithercraniuminthemiddle，shuntthetwohalvestotherightandleftandsendsurgingthroughthegapatumorwhichstavesthebarrelwithitspressure:thisconstitutestheFly’seccentricmethod。
Forwhatreasondoesthehernia，oncethekegisstaved，continueswollenandprojecting？Itakeittobeawastepocketintowhichtheinsectmomentarilyforcesbackitsreservesofbloodinordertodiminishthebulkofthebodytothatextentandtoextractitmoreeasilyfromthenymphalsloughandafterwardsfromthenarrowchanneloftheshell。Aslongastheoperationofthereleaselasts，itpushesoutsideallthatitisabletoinjectofitsaccumulatedhumors;itmakesitselfsmallinsidethepupaandswellsintoabloateddeformitywithout。Twohoursandmorearespentinthislaboriousstripping。
Atlast，theflycomesintoview。Thewings，merescantystumps，hardlyreachthemiddleoftheabdomen。Ontheouteredge，theyhaveadeepnotchsimilartothewaistofaviolin。Thisdiminishesbyjustsomuchthesurfaceandthelength，anexcellentdevicefordecreasingthefrictionalongtheearthycolumnwhichhasnexttobescaled。Thehydrocephalousoneresumesherperformancemorevigorouslythanever;sheinflatesanddeflatesherfrontalknob。Thepoundedsandrustlesdowntheinsect’ssides。Thelegsplaybutasecondarypart。Stretchedbehind，motionless，whenthepistonstrokeisdelivered，theyfurnishasupport。Asthesanddescends，theypileitandnimblypushitback，afterwhichtheydragalonglifelesslyuntilthenextavalanche。Theheadadvanceseachtimebyalengthequaltothatofthesanddisplaced。Eachstrokeofthefrontalswellingmeansastepforward。Inadry，loosesoil，thingsgoprettyfast。A
columnsixincheshighistraversedinlessthanaquarterofanhour。
Assoonasitreachesthesurface，theinsect，coveredwithdust，proceedstomakeitstoilet。Itthrustsouttheblisterofitsforeheadforthelasttimeandbrushesitcarefullywithitsfronttarsi。Itisimportantthatthelittlepoundingengineshouldbecarefullydustedbeforeitistakeninsidetoformaforeheadthatwillopennomore:thislestanygritshouldlodgeinthehead。
Thewingsarecarefullybrushedandpolished;theylosetheircurvednotches;theylengthenandspread。Then，motionlessonthesurfaceofthesand，theflymaturesfully。Letussetheratliberty。ShewillgoandjointheothersontheSnakesinmypans。
CHAPTERXITHEBUMBLEBEEFLY
Underneaththewasp’sbrownpapermanorhouse，thegroundischanneledintoasortofdrainfortherefuseofthenest。Hereareshotthedeadorweaklylarvaewhichacontinualinspectionrootsoutfromthecellstomakeroomforfreshoccupants;here，atthetimeoftheautumnmassacre，areflungthebackwardgrubs;
here，lastly，liesagoodpartofthecrowdkilledbythefirsttouchofwinter。DuringtherackandruinofNovemberandDecember，thissewerbecomescrammedwithanimalmatter。
Suchricheswillnotremainunemployed。Theworld’sgreatlawwhichsaysthatnothingedibleshallbewastedprovidesfortheconsumptionofamereballofhairdisgorgedbytheowl。Howshallitbewiththevaststoresofaruinedwasps’nest！Iftheyhavenotcomeyet，theconsumerswhosetaskitistosalvethisabundantwreckagefornature’smarkets，theywillnottarryincomingandwaitingforthemannathatwillsoondescendfromabove。Thatpublicgranary，lavishlystockedbydeath，willbecomeabusyfactoryoffreshlife。Whoaretheguestssummonedtothebanquet？
Ifthewaspsflewaway，carryingthedeadorsicklygrubswiththem，anddroppedthemonthegroundroundabouttheirhome，thosebanqueterswouldbe，firstandforemost，theinsect—eatingbirds，thewarblers，allofwhomareloversofsmallgame。Inthisconnection，wewillallowourselvesabriefdigression。Weallknowwithwhatjealousintolerancethenightingalesoccupyeachhisowncantonment。Neighborlyintercourseamongthemistabooed。Themalesfrequentlyexchangedefiantcoupletsatadistance;but，shouldthechallengedpartydrawnear，thechallengermakeshimclearoff。Now，notfarfrommyhouse，inascantyclumpofhollyoakswhichwouldbarelygivethewoodcutterthewherewithalforadozenfaggots，Iused，allthroughthespring，tohearsuchfull—
throatedwarblingofnightingalesthatthesongsofthosevirtuosi，allgivingvoiceatonceandwithnoattemptatorder，degeneratedintoadeafeninghubbub。
Whydidthosepassionatedevoteesofsolitudecomeandsettleinsuchlargenumbersataspotwherecustomdecreesthatthereisjustroomenoughforonehouseholdonly？Whatreasonshavemadethereclusebecomeacongregation？Iaskedtheownerofthespinneyaboutthematter。
’It’slikethateveryyear，’hesaid。’TheclumpisoverrunbyNightingales。’
’Andthereason？’
’Thereasonisthatthereisahivecloseby，behindthatwall。’
Ilookedatthemaninamazement，unabletounderstandwhatconnectiontherecouldbebetweenahiveandthethrongingnightingales。
’Why，yes，’headded，’therearealotofnightingalesbecausetherearealotofbees。
Anotherquestioninglookfrommyside。Ididnotyetunderstand。
Theexplanationcame:’Thebees，’hesaid，’throwouttheirdeadgrubs。Thefrontofthehiveisstrewnwiththeminthemornings;
andthenightingalescomeandcollectthemforthemselvesandtheirfamilies。Theyareveryfondofthem。’
ThistimeIhadsolvedthepuzzle。Deliciousfood，abundantandfresheachday，hadbroughtthesongsterstogether。Contrarytotheirhabit，numbersofnightingalesarelivingonfriendlytermsinaclusterofbushes，inordertobenearthehiveandtohavealargershareinthemorningdistributionofplumpdainties。
Inthesameway，thenightingaleandhisgastronomicalrivalswouldhaunttheneighborhoodofthewasps’nests，ifthedeadgrubswerecastoutonthesurfaceofthesoil;butthesedelicaciesfallinsidetheburrowandnolittlebirdwoulddaretoenterthemurkycave，eveniftheentrancewerenottoosmalltoadmitit。Otherconsumersareneededhere，smallinsizeandgreatindaring;theflyiscalledforandhermaggot，thekingofthedeparted。Whatthegreenbottles，thebluebottlesandthefleshfliesdointheopenair，attheexpenseofeverykindofcorpse，otherflies，narrowingtheirprovince，doundergroundattheWasps’expense。
Letusturnourattention，inSeptember，tothewrapperofawasps’
nest。Ontheoutersurfaceandtherealone，thiswrapperisstrewnwithamultitudeofbig，white，ellipticaldots，firmlyfixedtothebrownpaperandmeasuringabouttwomillimetersandahalflongbyoneandahalfwide。Flatbelow，convexaboveandofalustrouswhite，thesedotsresembleveryneatdropsfallenfromatallowcandle。Lastly，theirbacksarestreakedwithfainttransversallines，anelegantdetailperceptibleonlywiththelens。Thesecuriousobjectsarescatteredalloverthesurfaceofthewrapper，sometimesatadistancefromoneanother，sometimesgatheredintomoreorlessdensegroups。TheyaretheeggsoftheVolucella，orbumblebeefly（Volucellazonaria，LIN。）
AlsostucktothebrownpaperoftheouterwrapperandmixedupwiththeVolucella’sarealargenumberofothereggs，chalkwhite，spear—shapedandridgedlengthwisewithsevenoreightthinribs，afterthemanneroftheseedsofcertainUmbelliferae。Thefinishingtouchtotheirdelicatebeautyisthefinestipplingalloverthesurface。Theyaresmallerbyhalfthantheothers。I
haveseengrubscomeoutofthemwhichmighteasilybetheearlieststageofsomepointedmaggotswhichIhavealreadynoticedintheburrows。Myattemptstorearthemfailed;andIamnotabletosaywhichflytheseeggsbelongto。Enoughforustonotethenamelessoneinpassing。Thereareplentyofothers，whichwemustmakeupourmindstoleaveunlabelled，inviewofthejumbledcrowdoffeastersintheruinedwasps’nest。Wewillconcernourselvesonlywiththemostremarkable，inthefrontrankofwhichstandsthebumblebeeFly。
Sheisagorgeousandpowerfulfly;andhercostume，withitsbrownandyellowbands，showsavagueresemblancetothatofthewasps。
OurfashionabletheoristshaveavailedthemselvesofthisbrownandyellowtocitetheVolucellaasastrikinginstanceofprotectivemimicry。Obliged，ifnotonherownbehalf，atleastonthatofherfamily，tointroduceherselfasaparasiteintothewasp’shome，sheresorts，theytellus，totrickeryandcraftilydonshervictim’slivery。Onceinsidethewasps’nest，sheistakenforoneoftheinhabitantsandattendsquietlytoherbusiness。
Thesimplicityofthewasp，dupedbyaveryclumsyimitationofhergarb，andthedepravityofthefly，concealingheridentityunderacounterfeitpresentment，exceedthelimitsofmycredulity。ThewaspisnotsosillynortheVolucellasocleverasweareassured。
IfthelatterreallymeanttodeceivetheWaspbyherappearance，wemustadmitthatherdisguiseisnonetoosuccessful。Yellowsashesroundtheabdomendonotmakeawasp。Itwouldneedmorethanthatand，aboveall，aslenderfigureandanimblecarriage;
andtheVolucellaisthicksetandcorpulentandsedateinhermovements。Neverwillthewasptakethatunwieldyinsectforoneofherownkind。Thedifferenceistoogreat。
PoorVolucella，mimesishasnottaughtyouenough。Youought——thisistheessentialpoint——tohaveadoptedawasp’sshape;andthatyouforgottodo:youremainedafatfly，easilyrecognizable。
Nevertheless，youpenetrateintotheterriblecavern;youareabletostaythereforalongtime，withoutdanger，astheeggsprofuselystrewnonthewrapperofthewasps’nestshow。Howdoyousetaboutit？
Letus，firstofall，rememberthatthebumblebeeflydoesnotentertheenclosureinwhichthecombsareheaped:shekeepstotheoutersurfaceofthepaperrampartandtherelayshereggs。Letus，ontheotherhand，recallthePolistes[atreenestingwasp]
placedinthecompanyofthewaspsinmyvivarium。Hereofasuretyisonewhoneednothaverecoursetomimicrytofindacceptance。Shebelongstotheguild，sheisawaspherself。Anyofusthathadnotthetrainedeyeoftheentomologistwouldconfusethetwospecies。Well，thisstranger，aslongasshedoesnotbecometooimportunate，isquitereadilytoleratedbythecagedwasps。Noneseekstopickaquarrelwithher。Sheisevenadmittedtothetable，thestripofpapersmearedwithhoney。Butsheisdoomedifsheinadvertentlysetsfootuponthecombs。Hercostume，hershape，hersize，whichtallyalmostexactlywiththecostume，shapeandsizeofthewasp，donotsaveherfromherfate。
SheisatoncerecognizedasastrangerandattackedandslaughteredwiththesamevigorasthelarvaeoftheHylotomasawflyandtheSaperdabeetle，neitherofwhichbearsanyoutwardresemblancetothelarvaofthewasps。
SeeingthatidentityofshapeandcostumedoesnotsavethePolistes，howwilltheVolucellafare，withherclumsyimitation？
Thewasp’seye，whichisabletodiscernthedissimilarinthelike，willrefusetobecaught。Themomentsheisrecognized，thestrangeriskilledonthespot。Astothatthereisnottheshadowofadoubt。
Intheabsenceofbumblebeefliesatthemomentofexperimenting，I
employanotherfly，Milesiafulminans，who，thankstoherslimfigureandherhandsomeyellowbands，presentsamuchmorestrikinglikenesstothewaspthandoesthefatVolucellazonaria。Despitethisresemblance，ifsherashlyventureonthecombs，sheisstabbedandslain。Heryellowsashes，herslenderabdomendeceivenobody。Thestrangerisrecognizedbehindthefeaturesofadouble。
Myexperimentsunderglass，whichvariedaccordingtothecaptureswhichIhappenedtomake，allleadmetothisconclusion:aslongasthereismorepropinquity，evenaroundthehoney，theotheroccupantsaretoleratedfairlywell;but，iftheytouchthecells，theyareassaultedandoftenkilled，withoutdistinctionofshapeorcostume。Thegrubs’dormitoryisthesanctumsanctorumwhichnooutsidermustenterunderpainofdeath。