The Life of the Fly

第3章

Itisapunylittleinsect,almostastinyasthemidgeswhomweseeeddyinginarayofsunshineattheendofautumn。Itsdressisgoldenbronze;itseyesarecoralred。Itcarriesanakedsword,thatistosay,thesheathofitsdrillstandsoutslantwiseatthetipofitsbelly,insteadoflyinginahollowgroovealongtheback,asitdoeswiththeLeucospis。Thisscabbardholdsthelatterhalfoftheinoculatingfilament,whichextendsbelowtheanimaltothebaseoftheabdomen。Inshort,itsutensilisthatoftheLeucospis,withthisdifference,thatitslowerhalfsticksoutlikearapier。

Thismitethatbearsasworduponherrumpisyetanotherpersecutorofthemasonbeesandnotoneoftheleastformidable。

SheexploitstheirnestsatthesametimeastheLeucospis。Iseeher,liketheLeucospis,slowlyexplorethegroundwithherantennae;Iseeher,liketheLeucospis,bravelydriveherdaggerintothestonewall。Moretakenupwithherwork,lessconsciousperhapsofdanger,shepaysnoheedtothemanwhoisobservinghersoclosely。WheretheLeucospisflies,shedoesnotbudge。Sogreatisherassurancethatshecomesrightintomystudy,tomyworktable,anddisputesmyownershipofthenestswhoseoccupantsIamexamining。Sheoperatesundermylens,sheoperatesjustbesidemyforceps。Whatriskdoessherun?Whatcanonedotoathingsoverysmall?SheissocertainofhersafetythatIcantaketheMason’snestinmyhand,moveit,putitdownandtakeitupagainwithouttheinsect’sraisinganyobjection:itcontinuesitsworkevenwhenmymagnifyingglassisplacedoverit。

OneoftheseheroineshascometoinspectanestoftheChalicodomaoftheWalls,mostofwhosecellsareoccupiedbythenumerouscocoonsofaparasite,theStelis。Thecontentsofthesecells,whichhavebeenpartiallyrippeduptosatisfymycuriosity,areverymuchexposedtoview。Thewindfallappearstobeappreciated,forIseethedwarfferretaboutfromcelltocellforfourdaysonend,seeherchoosehercocoonandinsertherawlinthemostapprovedfashion。Ithuslearnthatsight,althoughanindispensableguideinsearching,doesnotdecideupontheproperspotfortheoperation。Hereisaninsectexploringnotthestonyexteriorofthemason’sdwelling,butthesurfaceofcocoonswovenofsilk。Theexplorerhasneverfoundherselfplacedinsuchcircumstances,norhasanyofherracebeforeher,everycocoon,undernormalconditions,beingprotectedbyasurroundingwall。Nomatter:despitetheprofounddifferenceinthesurfaces,theinsectdoesnotwaver。Warnedbyaspecialsense,anundecipherableriddletoourselves,itknowsthattheobjectofitssearchlieshiddenunderthisunfamiliarcasing。

Thesenseofsmellhasalreadybeenshowntobeoutofthequestion;thatofsightisnoweliminatedinitsturn。

ThatsheshouldborethroughthecocoonsoftheStelis,aparasiteofthemasonbee,doesnotsurprisemeatall:Iknowhowindifferentmyboldvisitoristothenatureofthevictualsdestinedforherfamily。Ihavenoticedherpresenceinthehomesofbeesdifferinggreatlyinsizeandhabits:Anthophorae,Osmiae,Chalicodomae,Anthidia。TheStelisexploitedonmytableisonevictimmore;andthatisall。Theinterestdoesnotliethere。

Theinterestliesinthemaneuversoftheinsect,whichIamabletofollowunderthemostfavorableconditions。

Bentsharplyatrightangles,likeacoupleofbrokenmatches,theantennaefeelthecocoonwiththeirtipsalone。Theterminaljointisthehomeofthisstrangesensewhichdiscernsfromafarwhatnoeyesees,noscentdistinguishesandnoearhears。Ifthepointexploredbefoundsuitable,theinsecthoistsitselfontiptoesoastogivefullscopetotheplayofitsmechanism;itbringsthetipofthebellyalittleforward;andtheentireovipositor——

inoculating—needleandscabbard——standsperpendiculartothecocoon,inthecenterofthequadrilateraldescribedbythefourhindlegs,aneminentlyfavorablepositionforobtainingthemaximumeffect。Forsometime,thewholeoftheawlbearsonthecocoon,feelingallroundwithitspoint,gropingabout;then,suddenly,theboringneedleisreleasedfromitssheath,whichfallsbackalongthebody,whiletheneedlestrivestomakeitsentrance。Theoperationisadifficultone。Iseetheinsectmakeascoreofattempts,oneaftertheother,withoutsucceedinginpiercingthetoughwrapperoftheStelis。Shouldtheinstrumentnotpenetrate,itretreatsintoitssheathandtheinsectresumesitsscrutinyofthecocoon,soundingitpointbypointwiththetipsofitsantennae。Thenfurtherthrustsaretrieduntilonesucceeds。

Theeggsarelittlespindles,whiteandgleaminglikeivory,abouttwo—thirdsofamillimeterinlength。Theyhavenotthelong,curvedpeduncleoftheLeucospis’eggs;theyarenotsuspendedfromtheceilingofthecocoonlikethese,butarelaidwithoutorderaroundthefosteringlarva。Lastly,inasinglecellandwithasinglemother,thereisalwaysmorethanonelaying;andthenumberofeggsvariesconsiderablyineach。TheLeucospis,becauseofhergreatsize,whichrivalsthatofhervictim,theBee,findsineachcellprovisionsenoughforoneandonealone。When,therefore,thereismorethanonesetofeggsinanyonecell,thisisduetoamistakeonherpartandnotapremeditatedresult。Wherethewholerationisrequiredforthemealsofasinglegrub,shewouldtakegoodcarenottoinstallseveralifshecouldhelpit。Hercompetitorisnotcalledupontoobservethesamediscretion。A

Chalicodomagrubgivesthedwarfthewherewithaltoportionascoreofherlittleones,whowillliveincommonandinallcomfortonwhatasinglesonofthegiantesswouldeatupbyhimself。Thetinyboringengineer,therefore,alwayssettlesanumerousfamilyatthesamebanquet。Thebowl,ampleforadozenortwo,isemptiedinperfectharmony。

Curiositymademecountthebrood,toseeifthemotherwasabletoestimatethevictualsandtoproportionthenumberofgueststothesumptuousnessofthefareprovided。Mynotesmentionfifty—fourlarvaeinthecellofamaskedAnthophora(Anthophorapersonata)。

Noothercensusattainedthisfigure。Possibly,twodifferentmothershadlaidtheireggsinthiscrowdedhabitation。WiththeMasonbeeoftheWalls,Iseethenumberoflarvaevary,indifferentcells,betweenfourandtwenty—six;withthemasonbeeoftheSheds,betweenfiveandthirty—six;withthethree—hornedOsmia,whosuppliedmewiththelargestnumberofrecords,betweensevenandtwenty—five;withtheblueOsmia(Osmiacyanea,KIRB。),betweenfiveandsix;withtheStelis(Stelisnasuta),betweenfourandtwelve。

Thefirstreturnandthelasttwoseemtopointtosomerelationbetweentheabundanceofprovisionsandthenumberofconsumers。

WhenthemothercomesuponthebountifullarvaofthemaskedAnthophora,shegivesithalf—a—hundredtofeed;withtheStelisandtheblueOsmia,niggardlyrationsboth,shecontentsherselfwithhalf—a—dozen。Tointroduceintothediningroomonlythenumberofboardersthatthebilloffarewillallowwouldcertainlybeamostdeservingperformance,especiallyastheinsectisplacedunderverydifficultconditionstojudgethecontentsofthecell。

Thesecontents,whichliehiddenundertheceiling,areinvisible;

andtheinsectcanderiveitsinformationonlyfromtheoutsideofthenest,whichvariesinthedifferentspecies。Weshouldthereforehavetoadmittheexistenceofaparticularpowerofdiscrimination,asortofdiscernmentofthespecies,whichisrecognizedaslargeorsmallfromtheoutwardaspectofitshouse。Irefusetogotothislengthinmyconjectures,notthatinstinctseemstomeincapableofsuchfeats,butbecauseoftheparticularsobtainedfromthethree—hornedOsmiaandthetwomasonbees。

Inthecellsofthesethreespecies,IseethenumberoflarvaeputouttonursevaryinsoelasticafashionthatImustabandonallideaofproportionateadjustment。Themother,withouttroublingundulywhethertherebeanexcessoradearthofprovisionsforherfamily,hasfilledthecellsasherfancyprompted,orratheraccordingtothenumberofripeovulescontainedinherovariesatthetimeofthelaying。Iffoodbeover—plentiful,thebroodwillbeallthebetterforitandwillgrowbiggerandstronger;iffoodbescarce,thefamishedyoungsterswillnotdie,butwillremainsmaller。Indeed,withboththelarvaandthefullgrowninsect,I

haveoftenobservedadifferenceinsizewhichvariesaccordingtothedensityofthepopulation,themembersofasmallcolonybeingdoublethesizeoftheirovercrowdedneighbors。

Thegrubsarewhite,taperingatbothends,sharplysegmentedandcoveredallovertheirbodieswithacoatoffine,softhairswhichisinvisibleexceptunderthelens。Theheadconsistsofalittleknobmuchsmallerindiameterthanthebody。Inthishead,themicroscoperevealsmandiblesconsistingoffinespikesofatawnyred,whichspreadintoawide,colorlessbase。Deprivedofanyindentation,incapableofchewinganythingbetweentheirawl—shapedends,thesetwotoolsserveatbesttofixthegrubslightlyatsomepointofthefosteringlarva。Uselessforcarving,therefore,themouthisapureosculatorysucker,whichdrainstheprovisionsbyaprocessofexudationthroughtheskin。WeseehererepeatedwhattheAnthraxandtheLeucospishavealreadyshownus:thegradualexhaustionofavictimwhichtheparasiteconsumeswithoutkillingit。

ItisacuriousspectacleevenafterthatoftheAnthrax。Wehaveheretwentyorthirtystarvelings,allwiththeirmouthspressed,asforakiss,tothebodyoftheplumplarva,which,fromdaytoday,fadesandshrinkswithouttheleastappreciablewound,thuskeepingfreshuntilreducedtoashriveledslough。IfIdisturbthegluttonousswarm,all,withasuddenrecoil,letgo,dropoffandflounderaroundthefostermother。Theyarenolesspromptinresumingtheirsavagekisses。Ineednotaddthatneitheratthepointwheretheyleaveoffnoratthepointwheretheyrecommenceistherethefaintesttraceofliquid。Theoilyexudationoccursonlywhenthepumpisatwork。TolingeroverthisstrangemethodoffeedingissuperfluousafterwhatIhavesaidabouttheAnthrax。

Theappearanceofthefullgrowninsecttakesplaceatthebeginningofsummer,afternearlyawholeyear’sstayintheinvadeddwelling。Thelargenumberofinhabitantsofoneandthesamecellledmetothinkthattheworkofdeliveranceoughttopresentacertaininterest。Theyareallequallyanxioustoclearthewallsoftheprisonattheearliestpossiblemomentandtocomeforthintothegreatfestivalofthesun:dotheyallatthesametime,inaconfusedhorde,attacktheceilingwhichhastobepierced?Istheworkofdeliverancearrangedinthegeneralinterest?Orisindividualselfishnesstheonlyrule?Thesearethequestionswhichobservationwillanswer。

Alittleinadvanceoftheproperseason,Itransfereachfamilyintoashortglasstube,whichwillrepresentthenatalcell。A

good,thickcork,quiteacentimeterdeep,istheobstacletobepiercedforanoutlet。Well,insteadofthemadhasteandtheruinouslackoforganizationwhichIexpectedtofind,mybroodsshowmeintheirglassprisonanexceedinglywellregulatedworkshop。Oneinsect,oneonly,worksatperforatingthecork。

Patiently,withitsmandibles,grainbygrain,itdigsatunnelthewidthofitsbody。Thegalleryissonarrowthat,inordertoreturntothetube,theworkerhastomovebackwards。Itisaslowprocess;andittakeshoursandhourstodigthehole,ahardjobforthefrailminer。

Shouldherfatiguebecometoogreat,theexcavatorleavestheforefrontandmingleswiththecrowd,topolishanddustherself。

Another,thefirstneighborathand,atoncetakesherplaceandisherselfrelievedbyathirdwhenhertaskisdone。Othersagaintaketheirturn,alwaysoneatatime,somuchsothattheworksareneveratastandstillandneverovercrowded。Meanwhile,themultitudekeepsoutoftheway,quietlyandpatiently。Thereisnoanxietyastothedeliverance。Successwillcome:ofthattheyareallconvinced。Whilewaiting,onewashesherantennaebypassingthemthroughhermouth,anotherpolishesherwingswithherhindlegs,anotherfrisksabouttowhileawaytheperiodofinaction。

Somearemakinglove,asovranmeansofkillingtime,whetheronebebornthatdayortwentyyearsago。

Some,Isaid,makelove。Thesefavoredonesarerare;theyhardlycount。Isitthroughindifference?No,butthegallantsarelacking。Thesexesareveryunequallyrepresentedinthepopulationofacell:themalesareinawretchedminorityandsometimesevencompletelyabsent。Thispovertydidnotescapetheolderobservers。Brulle[GaspardAugustBru11e(1809—1873)],theauthorofmanyworksonnaturalhistoryandoneofthefoundersoftheSocieteentomologiquedeFrance),theonlyauthorwhomIamabletoconsultinmyhermitage,says,literally:’Themalesdonotappeartobeknown。’

I,formypart,knowthem;but,consideringtheirfeeblenumber,I

keepaskingmyselfwhatparttheyplayinaharemsodisproportionatetotheirforces。Afewfigureswillshowuswhatmyhesitationsarebasedupon。

Intwenty—twoOsmiacocoons(Osmiatricornis),thetotalcensusoftheinmatesyieldsthreehundredandfifty—four,ofwhomforty—

sevenaremalesandthreehundredandsevenfemales。Theaveragenumberofinmates,therefore,issixteenindividuals;andtherearesixfemalesatleasttoonemale。Thisdisparityismaintained,inmoreorlessmarkedproportions,whateverthespeciesofthebeeinvaded。InthecocoonsoftheMasonbeeoftheSheds,Idiscovertheaverageproportiontobesixfemalestoonemale;inthoseoftheMasonbeeoftheWalls,Ifindonemaletofifteenfemales。

Thesefacts,whichIamunabletostatewithanygreaterprecision,areenoughtogiverisetothesuspicionthatthemales,whoareeventinierdwarfsthanthefemalesandwho,moreover,likeallinsects,areinjuredbyasingleactofpairing,must,inmostcases,remainstrangerstothefemales。Canthemothers,infact,dispensewiththeirassistance,withoutbeingdeprivedofoffspringonthataccount?Idonotsayyes,butIdonotsayno。Thedualityofthesexesisahardproblem。Whytwosexes?Whynotjustone?Itwouldhavebeenmuchsimplerandsavedagreatdealoffoolery。Whysuchathingassex,whenthetuberoftheJerusalemartichokecandowithoutit?Thesearethepregnantquestionssuggestedtome,intheend,byMonodontomeruscupreus,theinsectsoinfinitesimalinbodyandsooverpoweringinnamethatIhadreallyvowednevertospeakofitagainbyitsofficialdesignation。

CHAPTERIVLARVALDIMORPHISM

IfthereaderhaspaidanyattentiontothestoryoftheAnthrax,hemusthaveperceivedthatmynarrativeisincomplete。Thefoxinthefablesawhowthelion’svisitorsenteredhisden,butdidnotseehowtheywentout。Withus,itistheconverse:weknowthewayoutofthemasonbee’sfortress,butwedonotknowthewayin。

Toleavethecellofwhichhehaseatentheowner,theAnthraxbecomesaperforatingmachine,alivingtoolfromwhichourownindustrymighttakeahintifitrequirednewdrillsforboringrocks。Whentheexittunnelisopened,thistoolsplitslikeapodburstinginthesun;andfromthestoutframeworkthereescapesadaintyfly,avelvetyflake,asoftfluffthatastoundsusbyitscontrastwiththeroughnessofthedepthswhenceitascends。Onthispoint,weknowprettywellwhatthereistoknow。Thereremainstheentranceintothecell,apuzzlethathaskeptmeonthealertforaquarterofacentury。

Tobeginwith,itisevidentthatthemothercannotlodgeheregginthecellofthemasonbee,whichhasbeenlongclosedandbarricadedwithacementwallbythetimethattheAnthraxmakesherappearance。Topenetrateit,shewouldhavetobecomeanexcavatingtooloncemoreandresumethecast—offragswhichsheleftbehindintheexitwindow;shewouldhavetoretracehersteps,toberebornapupa;andlifeknowsnoneoftheseretrogressions。Thefullgrowninsect,ifendowedwithclaws,mandiblesandplentyofperseverance,mightatapinchforcethemortarcasket;buttheflyisnotsoendowed。Herslenderlegswouldbestrainedanddeformedbymerelysweepingawayalittledust;hermouthisasuckerforgatheringthesugaryexudationsoftheflowersandnotthesolidpincersneededforthecrumblingofcement。Thereisnoaugereither,noborecopiedfromthatoftheLeucospis,noimplementofanykindthatcanworkitswayintothethicknessofthewallanddispatchtheeggtoitsdestination。Inshort,themotherisabsolutelyincapableofsettlinghereggsinthechamberoftheMasonbee。

Canitbethegrubthatmakesitsownwayintothestoreroom,thatsamegrubwhichwehaveseendrainingtheChalicodomawithitsleech—likekisses?Letuscallthecreaturetomind:alittleoilysausage,whichstretchesandcurlsupjustwhereitlies,withoutbeingabletoshiftitsposition。Itsbodyisasmoothcylinder;

itsmouthsimplyacircularlip。Notoneambulatoryorgandoesitpossess;notevenhairs,protuberancesorwrinklestoenableittocrawl。Theanimalismadefordigestionandimmobility。Itsorganizationisincompatiblewithmovement;everythingtellsussointheclearestfashion。No,thisgrubisevenlessablethanthemothertomakeitswayunaidedintothemason’sdwelling。Andyettheprovisionsarethere;thoseprovisionsmustbereached:itisamatteroflifeordeath;tobeornottobe。Thenhowdoestheflysetaboutit?Itwouldbevainformetoquestionprobabilities,toooftenillusory;toobtainareplyofanyvalue,Ihavebutoneresource;ImustattemptthenearlyimpossibleandwatchtheAnthraxfromtheeggonwards。

AlthoughAnthraxfliesarefairlycommon,inthesenseoftherebeingseveraldifferentspecies,theyarenotplentifulwhenitisacaseofwantingacolonypopulousenoughtoadmitofcontinuousobservation。Iseethem,nowhere,nowthere,inthefiercelysun—

scorchedplaces,flittinghitherandthitherontheoldwalls,theslopesandthesand,sometimesinsmallplatoons,mostoftensingly。Icanexpectnothingofthosevagabonds,whoareheretodayandgonetomorrow,forIknownothingoftheirsettlements。

Tokeepawatchonthem,onebyone,intheblazingheat,isverypainfulandveryunfruitful,astheswift—wingedinsecthasahabitofdisappearingoneknowsnotwhitherjustwhenaprospectofcapturingitssecretbeginstooffer。Ihavewastedmanyapatienthouratthispursuit,withouttheleastresult。

TheremightbesomechanceofsuccesswithAnthraxflieswhosehomewasknowntousbeforehand,especiallyifinsectsofthesamespeciesformedaprettynumerouscolony。Theinquiriesbegunwithonewouldbecontinuedwithasecondandwithmore,untilacompleteverdictwasforthcoming。Now,inthecourseofmylongentomologicalcareer,IhavemetwithbuttwospeciesofAnthraxthatfulfilledthisconditionandweretobefoundregularly:oneatCarpentras;theotheratSerignan。Thefirst,Anthraxsinuata,FALLEN,livesinthecocoonsofOsmiatricornis,whoherselfbuildshernestintheoldgalleriesofthehairy—footedAnthophora;thesecond,Anthraxtrifasciata,MEIGEN,exploitstheChalicodomaoftheSheds。Iwillconsultboth。

Oncemore,hereamI,somewhatlateinlife,atCarpentras,whoserudeGallicnamesetsthefoolsmilingandthescholarthinking。

DearlittletownwhereIspentmytwentiethyearandleftthefirstbitsofmyfleeceuponlife’sbushes,myvisitoftodayisapilgrimage;Ihavecometolaymyeyesoncemoreupontheplacewhichsawthebirthoftheliveliestimpressionsofmyearlydays。

Ibow,inpassing,totheoldcollegewhereItriedmyprenticehandasateacher。Itsappearanceisunchanged;itstilllookslikeapenitentiary。Thoseweretheviewsofourmediaevaleducationalsystem。Tothegaietyandactivityofboyhood,whichwereconsideredunwholesome,itappliedtheremedyofnarrowness,melancholyandgloom。Itshousesofinstructionwere,aboveall,housesofcorrection。ThefreshnessofVirgilwasinterpretedinthestiflingatmosphereofaprison。Icatchaglimpseofayardbetweenfourhighwalls,asortofbearpit,wherethescholarsfoughtforroomfortheirgamesunderthespreadingbranchesofaplanetree。Allaroundwerecellsthatlookedlikehorseboxes,withoutlightorair;thoseweretheclassrooms。Ispeakinthepasttense,fordoubtlessthepresentdayhasseenthelastofthisacademicdestitution。

Hereisthetobaccoshopwhere,onWednesdayevening,comingoutofthecollege,Iwouldbuyoncreditthewherewithaltofillmypipeandthustocelebrateontheevethejoysofthemorrow,thatblessedThursday[theweeklyhalf—holidayinFrenchschools]whichIconsideredsowellemployedinsolvinghardequations,experimentingwithnewchemicalreagents,collectingandidentifyingmyplants。Iwouldmakemytimidrequest,pretendingtohavecomeoutwithoutmymoney,foritishardforaself—

respectingmantoadmitthatheispenniless。Mycandorappearstohaveinspiredsomelittleconfidence;andIobtainedcredit,anunprecedentedthing,withtherepresentativeoftherevenue。[ThegovernmentinFrancehasthesolecontrolofthetobaccotrade,whichformsanimportantbranchoftheinlandrevenue。]Ah,whydidnotIopenashopandexposeforsalesomepacketsofcandles,adozendriedcod,abarrelofsardinesandafewcakesofsoap!Iamnomoreofafoolnoranylessindustriousthananother;andI

shouldhavemademyway。But,asitwas,whatcouldIexpect?Asanaccoucheurofbrains,amolderofintellects,Ihadnoclaimeventobreadandcheese。

Hereismyformerhabitation,occupiedsincebydroningmonks。Intheembrasureofthatwindow,shelteredfromprofanehands,betweentheclosedoutershuttersandthepanes,Iusedtokeepmychemicals,boughtforafewsouscheatedoutoftheweeklybudgetintheearlydaysofourhousekeeping。Thebowlofapipewasmycrucible,asweetjarmyretort,mustardpotsmyreceptaclesforoxidesandsulfides。Myexperiments,harmlessordangerous,weremadeonacornerofthefirebesidethesimmeringbroth。

HowIshouldlovetoseethatroomagainwhereIporedoverdifferentialsandintegrals,whereIcalmedmypoorburningheadbygazingatMontVentoux,whosesummitheldinstoreformycomingexpedition’thosedenizensofarcticclimes,thesaxifrageandthepoppy!Andtoseemyfamiliarfriend,theblackboardwhichIhiredatfivefrancsayearfromacrustyjoiner,thatboardwhosevalueIpaidmanytimesover,thoughI。couldneverbuyitoutright,forwantofthenecessarycash!TheconicsectionswhichIdescribedonthatblackboard,thelearnedhieroglyphics!

Thoughallmyefforts,whichwerethemoredeservingbecauseIhadtoworkalone,ledtoalmostnothinginthatcongenialcalling,I

wouldbeginitalloveragainifIcould。IshouldlovetobeconversingforthefirsttimewithLeibnitzandNewton,withLaplaceandLagrange,withCuvierandJussieu,evenifIhadafterwardstosolvethatotherarduousproblem:howtoprocureone’sdailybread。Ah,youngmen,mysuccessors,whataneasytimeyouhaveofittoday!Ifyoudon’tknowit,thenletmetellyousobymeansofthesefewpagesfromthelifeofoneofyourelders。

Butletusnotforgetourinsects,whilelisteningtotheechoesofillusionsanddifficultiesrousedinmymemoriesbythecupboardwindowandthehiredblackboard。LetusgobacktothesunkenroadsoftheLegue,whichhavebecomeclassic,sotheysay,sincetheappearanceofmynotesontheOilbeetles。Yeillustriousravines,withyoursun—bakedslopes,ifIhavecontributedalittletoyourfame,you,inyourturn,havegivenmemanyfairhoursofforgetfulnessinthehappinessoflearning。You,atleast,didnotluremewithvainhopes;allthatyoupromisedyougavemeandoftenahundredfold。Youaremypromisedland,whereIwouldhavesoughtatthelasttopitchmyobserver’stent。Mywishwasnottoberealized。Letme,atleast,inpassing,greetmybelovedanimalsoftheolddays。

IraisemyhattoCerceristuberculata,whomIseeengagedonthatslant,storingherCleonus[alargespeciesofweevil]。AsIsawherthen,soIseehernow:thesamestaggeringattemptstohoistthepreytothemouthoftheburrow;thesamebrawlsbetweenmaleswatchinginthebrushwoodofthekermesoak。Thesightofthemsendsayoungerbloodcoursingthroughmyveins;Ireceiveasitwerethebreathofanewspringtimeoflife。Timepresses;letuspasson。

Anotherbowonthisside。Ihearbuzzingupabove,onthatledge,acolonyofSphexwasps,stabbingtheircrickets。Wewillgivethemafriendlyglance,butnomore。Myacquaintancesherearetoonumerous;Ihavenottheleisuretorenewmyformerrelationswithallofthem。Withoutstopping,awaveofthehattothePhilanthi[bee—huntingwasps]whosendthelongavalanchesofrubbishstreamingdownfromtheirnests;andtoStizusruficornis,[ahuntingwasp]whostacksherprayingmantisesbetweentwoflakesofsandstone;andtothesilkyAmmophila[adiggerwasp]withtheredlegs,whocollectsanundergroundstoreofloopers[alsoknownasmeasuringworms,thelarvaeorcaterpillarsofthegeometridmoth]

andtotheTachtyti[huntingwasps],devourersoflocusts;andtotheEumenes,buildersofclaycupolasonabough。

Hereweareatlast。Thishigh,perpendicularrock,facingthesouthtoalengthofsomehundredsofyardsandriddledwithholeslikeamonstroussponge,isthetime—honoreddwellingplaceofthehairy—footedAnthophoraandofherrentfreetenant,thethree—

hornedOsmia。Herealsoswarmtheirexterminators:theSitarisbeetle,theparasiteoftheAnthophora;theAnthraxfly,themurdereroftheOsmia。Illinformedastotheproperperiod,I

havecomeratherlate,onthe10thofSeptember。Ishouldhavebeenhereamonthago,orevenbytheendofJuly,towatchthefly’soperations。Myjourneythreatenstobefruitless:IseebutafewrareAnthraxflies,hoveringroundthefaceofthecliff。Wewillnotdespair,however,andwewillbeginbyconsultingthelocality。

TheAnthophora’scellscontainthisbeeinthelarvalstage。SomeofthemprovidemewiththeoilbeetleandtheSitaris,rarefindsatonetime,todayofnousetome。OtherscontaintheMelecta[aparasiticbee]intheformofahighlycoloredpupa,oreveninthatofthefullgrowninsect。TheOsmia,stillmoreprecocious,thoughdatingfromthesameperiod,showsherselfexclusivelyintheadultform,abadomenformyinvestigations,forwhattheAnthraxdemandsisthelarvaandnottheperfectinsect。Thefly’sgrubdoublesmyapprehensions。Itsdevelopmentiscomplete,thelarvaonwhichitfeedsisconsumed,perhapsseveralweeksago。I

nolongerdoubtbutthatIhavecometoolatetoseewhathappensintheOsmia’scocoons。

Isthegamelost?Notyet。MynotescontainevidenceofAnthraxflieshatchinginthelatterhalfofSeptember。Besides,thosewhomInowseeexploringtherockarenottheretotakeexercise:

theirpreoccupationisthesettlingofthefamily。ThesebelatedonescannottackletheOsmia,who,withherfirm,adultflesh,wouldnotsuitthenursling’sdelicateneedsandwho,moreover,powerfulassheis,wouldofferresistance。Butinautumnalessnumerouscolonyofhoneygathererstakestheplace,upontheslope,ofthespringcolony,fromwhichitdiffersinspecies。Inparticular,IseetheDiademAnthidium[aclothierbeewholineshernestwithwoolandcotton]atwork,enteringhergalleriesatonetimewithherharvestofpollendustandatanotherwithherlittlebaleofcotton。MightnottheseautumnalBeesbethemselvesexploitedbytheAnthrax,thesamethatselectedtheOsmiaashervictimacoupleofmonthsearlier?ThiswouldexplainthepresenceoftheAnthraxflieswhomInowseefussingabout。

Alittlereassuredbythisconjecture,Itakemystandatthefootoftherock,underabroilingsun;and,forhalfaday,Ifollowtheevolutionsofmyflies。Theyflitquietlyinfrontoftheslope,atafewinchesfromtheearthycovering。Theygofromoneorificetothenext,butwithoutevenpenetrating。Forthatmatter,theirbigwings,extendedcrosswiseevenwhenatrest,wouldresisttheirentranceintoagallery,whichistoonarrowtoadmitthosespreadingsails。Andsotheyexplorethecliff,goingtoandfroandupanddown,withaflightthatisnowsudden,nowsmoothandslow。Fromtimetotime,IseetheAnthraxquicklyapproachthewallandlowerherabdomenasthoughtotouchtheearthwiththeendofherovipositor。Thisproceedingtakesnolongerthanthetwinklingofaneye。Whenitisdone,theinsectalightselsewhereandrests。Thenitresumesitssoberflight,itslonginvestigationsanditssuddenblowswiththetipofitsbellyagainstthelayerofearth。TheBombylii[beeflies]

observesimilartacticswhensoaringatashortheightabovetheground。

Iatoncerushedtothespottouched,lensinhand,inthehopeoffindingtheeggwhicheverythingtoldmewaslaidduringthattapoftheabdomen。Icoulddistinguishnothing,inspiteoftheclosestattention。Itistruethatmyexhaustion,togetherwiththeblindinglightandscorchingheat,madeexaminationverydifficult。Afterwards,whenImadetheacquaintanceofthetinythingthatissuesfromthategg,myfailurenolongersurprisedme。

Intheleisureofmystudy,withmyeyesrestedandwithmymostpowerfulglassesheldinahandnolongershakingwithexcitementandfatigue,Ihavetheverygreatestdifficultyinfindingtheinfinitesimalcreature,thoughIknowexactlywhereitlies。ThenhowcouldIseetheegg,wornoutasIwasunderthesun—bakedcliff,howdiscovertheprecisespotofalayingperformedinamomentbyaninsectseenonlyatadistance?InthepainfulconditionswhereinIfoundmyself,failurewasinevitable。

Despitemynegativeattempts,therefore,IremainconvincedthattheAnthraxfliesstrewtheireggsonebyone,onthespotsfrequentedbythosebeeswhosuittheirgrubs。Eachoftheirsuddenstrokeswiththetipoftheabdomenrepresentsalaying。

Theytakenoprecautiontoplacethegermundercover;forthatmatter,anysuchprecautionwouldberenderedimpossiblebythemother’sstructure。Theegg,thatdelicateobject,islaidroughlyintheblazingsun,betweengrainsofsand,insomewrinkleofthecalcinedchalk。Thatsummaryinstallationissufficient,providedthecovetedlarvabenearathand。Itisfortheyounggrubnowtomanageasbestitcanatitsownriskandperil。

ThoughthesunkenroadsoftheLeguedidnottellmeallthatI

wishedtoknow,theyatleastmadeitveryprobablethatthecominggrubmustreachthevictualledcellbyitsownefforts。Butthegrubwhichweknow,theonethatdrainsthebagoffatwhichmaybeaChalicodomalarvaoranOsmialarva,cannotmovefromitsplace,stilllessindulgeinjourneysofdiscoverythroughthethicknessofawallandthewebofacocoon。Soanimperativenecessitypresentsitself:theremustperforcebeaninitiallarvaform,capableofmovingandorganizedforsearching,aformunderwhichthegrubwouldattainitsend。TheAnthraxwouldthuspossesstwolarvalstates:onetopenetratetotheprovisions;theothertoconsumethem。Iallowmyselftobeconvincedbythelogicofitall;Ialreadyseeinmymind’seyetheweeanimalcomingoutoftheegg,endowedwithsufficientpowerofmotionnottodreadawalkandwithsufficientslendernesstoglideintothesmallestcrevices。Onceinthepresenceofthelarvaonwhichitistofeed,itdoffsitstravellingdressandbecomestheobeseanimalwhoseonedutyitistogrowbigandfatinimmobility。Thisisallverycoherent;itisalldeducedlikeageometricalproposition。Buttothewingsofimagination,howeversmooththeirflight,wemustpreferthesandalsofobservedfacts,theslowsandalswiththeleadensoles。Thusshod,Iproceed。

Nextyear,Iresumemyinvestigations,thistimeontheAnthraxoftheChalicodoma,whoismyneighborinthesurroundingwastelandsandwillallowmetorepeatmyvisitsdaily,morningandeveningifneedbe。Taughtbymyearlierstudies,InowknowtheexactperiodoftheBee’shatchingandthereforeoftheAnthrax’laying,whichmusttakeplacesoonafter。AnthraxtrifasciatasettlesherfamilyinJuly,orinAugustatlatest。Everymorning,atnineo’clock,whentheheatbeginstobeunendurableandwhen,touse[theauthor’sgardenerandfactotum]Favier’sexpression,anextralogisflungonthebonfireofthesun,Itakethefield,preparedtocomebackwithmyheadachingfromtheglare,providedthatIbringhomethesolutionofmypuzzle。Amanmusthavethedevilinhimtoleavetheshadeatthistimeoftheyear。Andwhatfor,pray?

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