第6章

Theoldmalecellscanberecognizedbytheirpositionontheouteredgesandbytheircapacity,measuringonanaveragethesameasacolumnofsand31millimetreshighinaglasstube5millimetreswide。（1。21x。195inches。——Translator\'sNote。）Thesecellscontainmalesofthesecondorthirdgenerationandnonebutmales。Intheoldfemalecells,thoseinthemiddle,whosecapacityismeasuredbyasimilarcolumnofsand45millimetreshigh（1。75inches。——

Translator\'sNote。）,arefemalesandnonebutfemales。

Thispresenceofbothsexesatatime,evenwhentherearebuttwocellsfree,onespaciousandtheothersmall,provesintheplainestfashionthattheregulardistributionobservedinthecompletenestsofrecentproductionisherereplacedbyanirregulardistribution,harmonizingwiththenumberandholding—capacityofthechamberstobestocked。TheMason—beehasbeforeher,letmesuppose,onlyfivevacantcells:twolargerandthreesmaller。Thetotalspaceatherdisposalwoulddoforaboutathirdofthelaying。Well,inthetwolargecells,sheputsfemales;inthethreesmallcells,sheputsmales。

Aswefindthesamesortofthinginalltheoldnests,wemustneedsadmitthatthemotherknowsthesexoftheeggwhichsheisgoingtolay,becausethateggisplacedinacellofthepropercapacity。Wecangofurtherandadmitthatthemotheralterstheorderofsuccessionofthesexesatherpleasure,becauseherlayings,betweenoneoldnestandanother,arebrokenupintosmallgroupsofmalesandfemalesaccordingtotheexigenciesofspaceintheactualnestwhichshehappenstobeoccupying。

Justnow,inthenewnest,wesawtheMason—beearranginghertotallayingintoseriesfirstoffemalesandnextofmales;andheresheis,mistressofanoldnestofwhichshehasnotthepowertoalterthearrangement,breakingupherlayingintosectionscomprisingbothsexesjustasrequiredbytheconditionsimposeduponher。Shethereforedecidesthesexoftheeggatwill,for,withoutthisprerogative,shecouldnot,inthechambersofthenestwhichsheowestochance,depositunerringlythesexforwhichthosechamberswereoriginallybuilt;andthishappenshoweversmallthenumberofchamberstobefilled。

Whenthenestisnew,IthinkIseeareasonwhytheMason—beeshouldseriateherlayingintofemalesandthenmales。Hernestisahalf—

sphere。ThatoftheMason—beeoftheShrubsisverynearlyasphere。

Ofallshapes,thesphericalshapeisthestrongest。Nowthesetwonestsrequireanexceptionalpowerofresistance。Withoutprotectionofanykind,theyhavetobravetheweather,oneonitspebble,theotheronitsbough。Theirsphericalconfigurationisthereforeverypractical。

ThenestoftheMason—beeoftheWallsconsistsofaclusterofuprightcellsbackingagainstoneanother。Forthewholetotakeasphericalform,theheightofthechambersmustdiminishfromthecentreofthedometothecircumference。Theirelevationisthesineofthemeridianarcstartingfromtheplaneofthepebble。Therefore,iftheyaretohaveanysolidity,theremustbelargecellsinthemiddleandsmallcellsattheedges。And,astheworkbeginswiththecentralchambersandendswiththoseonthecircumference,thelayingofthefemales,destinedforthelargecells,mustprecedethatofthemales,destinedforthesmallcells。Sothefemalescomefirstandthemalesatthefinish。

Thisisallverywellwhenthemotherherselffoundsthedwelling,whenshelaysthefirstrowsofbricks。But,whensheisinthepresenceofanoldnest,ofwhichsheisquiteunabletoalterthegeneralarrangement,howisshetomakeuseofthefewvacantrooms,thelargeandthesmallalike,ifthesexoftheeggbealreadyirrevocablyfixed？Shecanonlydosobyabandoningthearrangementintwoconsecutiverowsandaccommodatingherlayingtothevariedexigenciesofthehome。Eithershefindsitimpossibletomakeaneconomicaluseoftheoldnest,atheoryrefutedbytheevidence,orelseshedeterminesatwillthesexoftheeggwhichsheisabouttolay。

TheOsmiaethemselveswillfurnishthemostconclusiveevidenceonthelatterpoint。WehaveseenthattheseBeesarenotgenerallyminers,whothemselvesdigoutthefoundationoftheircells。Theymakeuseoftheoldstructuresofothers,orelseofnaturalretreats,suchashollowstems,thespiralsofemptyshellsandvarioushiding—placesinwalls,clayorwood。Theirworkisconfinedtorepairstothehouse,suchaspartitionsandcovers。Thereareplentyoftheseretreats;andtheinsectwouldalwaysfindfirst—

classonesifitthoughtofgoinganydistancetolookforthem。ButtheOsmiaisastay—at—home:shereturnstoherbirth—placeandclingstoitwithapatienceextremelydifficulttoexhaust。Itishere,inthislittlefamiliarcorner,thatshepreferstosettleherprogeny。Butthentheapartmentsarefewinnumberandofallshapesandsizes。Therearelongandshortones,spaciousonesandnarrow。

Shortofexpatriatingherself,aSpartancourse,shehastousethemall,fromfirsttolast,forshehasnochoice。Guidedbytheseconsiderations,IembarkedontheexperimentswhichIwillnowdescribe。

Ihavesaidhowmystudy,ontwoseparateoccasions,becameapopuloushive,inwhichtheThree—hornedOsmiabuilthernestsinthevariousapplianceswhichIhadpreparedforher。Amongtheseappliances,tubes,eitherofglassorreed,predominated。Thereweretubesofalllengthsandwidths。Inthelongtubes,entireoralmostentirelayings,withaseriesoffemalesfollowedbyaseriesofmales,weredeposited。AsIhavealreadyreferredtothisresult,I

willnotdiscussitagain。Theshorttubesweresufficientlyvariedinlengthtolodgeoneorotherportionofthetotallaying。Basingmycalculationsontherespectivelengthsofthecocoonsofthetwosexes,onthethicknessofthepartitionsandthefinallid,I

shortenedsomeofthesetotheexactdimensionsrequiredfortwococoonsonly,ofdifferentsexes。

Well,theseshorttubes,whetherofglassorreed,wereseizeduponaseagerlyasthelongtubes。Moreover,theyyieldedthissplendidresult:theircontents,onlyapartofthetotallaying,alwaysbeganwithfemaleandendedwithmalecocoons。Thisorderwasinvariable;

whatvariedwasthenumberofcellsinthelongtubesandtheproportionbetweenthetwosortsofcocoons,sometimesmalespredominatingandsometimesfemales。

Theexperimentisofparamountimportance;anditwillperhapsmaketheresultclearerifIquoteoneinstancefromamongamultitudeofsimilarcases。Igivethepreferencetothisparticularinstancebecauseoftheratherexceptionalfertilityofthelaying。AnOsmiamarkedonthethoraxiswatched,daybyday,fromthecommencementtotheendofherwork。Fromthe1sttothe10thofMay,sheoccupiesaglasstubeinwhichshelodgessevenfemalesfollowedbyamale,whichendstheseries。Fromthe10thtothe17thofMay,shecolonizesasecondtube,inwhichshelodgesfirstthreefemalesandthenthreemales。Fromthe17thtothe25thofMay,athirdtube,withthreefemalesandthentwomales。Onthe26thofMay,afourthtube,whichsheabandons,probablybecauseofitsexcessivewidth,afterlayingonefemaleinit。Lastly,fromthe26thtothe30thofMay,afifthtube,whichshecolonizeswithtwofemalesandthreemales。Total:twenty—fiveOsmiae,includingseventeenfemalesandeightmales。Anditwillnotbesuperfluoustoobservethattheseunfinishedseriesdonotinanywaycorrespondwithperiodsseparatedbyintervalsofrest。Thelayingiscontinuous,insofarasthevariableconditionoftheatmosphereallows。Assoonasonetubeisfullandclosed,anotherisoccupiedbytheOsmiawithoutdelay。

Thetubesreducedtotheexactlengthoftwocellsfulfilledmyexpectationinthegreatmajorityofcases:thelowercellwasoccupiedbyafemaleandtheupperbyamale。Therewereafewexceptions。MorediscerningthanIinherestimateofwhatwasstrictlynecessary,better—versedintheeconomyofspace,theOsmiahadfoundawayoflodgingtwofemaleswhereIhadonlyseenroomforonefemaleandamale。

Thisexperimentspeaksvolumes。Whenconfrontedwithtubestoosmalltoreceiveallherfamily,sheisinthesameplightastheMason—beeinthepresenceofanoldnest。ShethereuponactsexactlyastheChalicodomadoes。Shebreaksupherlaying,dividesitintoseriesasshortastheroomatherdisposaldemands;andeachseriesbeginswithfemalesandendswithmales。Thisbreakingup,ontheonehand,intosectionsinallofwhichbothsexesarerepresentedandthedivision,ontheotherhand,oftheentirelayingintojusttwogroups,onefemale,theothermale,whenthelengthofthetubepermits,surelyprovideuswithampleevidenceoftheinsect\'spowertoregulatethesexoftheeggaccordingtotheexigenciesofspace。

Andbesidestheexigenciesofspaceonemightperhapsventuretoaddthoseconnectedwiththeearlierdevelopmentofthemales。Thesebursttheircocoonsacoupleofweeksormorebeforethefemales;

theyarethefirstwhohastentothesweetsofthealmond—tree。Inordertoreleasethemselvesandemergeintothegladsunlightwithoutdisturbingthestringofcocoonswhereintheirsistersarestillsleeping,theymustoccupytheupperendoftherow;andthis,nodoubt,isthereasonthatmakestheOsmiaendeachofherbrokenlayingswithmales。Beingnexttothedoor,theseimpatientoneswillleavethehomewithoutupsettingtheshellsthatareslowerinhatching。

IexperimentedonLatreille\'sOsmia,usingshortandevenveryshortstumpsofreed。AllthatIhadtodowastolaythemjustbesidethenestsoftheMason—beeoftheSheds,nestsbelovedbythisparticularOsmia。Old,disusedhurdlessuppliedmewithreedsinhabitedfromendtoendbytheHornedOsmia。InbothcasesIobtainedthesameresultsandthesameconclusionsaswiththeThree—hornedOsmia。

Ireturntothelatter,nidifyingundermyeyesinsomeoldnestsoftheMason—beeoftheWalls,whichIhadplacedwithinherreach,mixedupwiththetubes。Outsidemystudy,IhadneveryetseentheThree—hornedOsmiaadoptthatdomicile。Thismaybeduetothefactthatthesenestsareisolatedonebyoneinthefields;andtheOsmia,wholovestofeelherselfsurroundedbyherkinandtoworkinplentyofcompany,refusesthembecauseofthisisolation。Butonmytable,findingthemclosetothetubesinwhichtheothersareworking,sheadoptsthemwithouthesitation。

ThechamberspresentedbythoseoldnestsaremoreorlessspaciousaccordingtothethicknessofthecoatofmortarwhichtheChalicodomahaslaidovertheassembledchambers。Toleavehercell,theMason—beehastoperforatenotonlytheplug,thelidbuiltatthemouthofthecell,butalsothethickplasterwherewiththedomeisstrengthenedattheendofthework。Theperforationresultsinavestibulewhichgivesaccesstothechamberitself。Itisthisvestibulewhichissometimeslongerandsometimesshorter,whereasthecorrespondingchamberisofalmostconstantdimensions,inthecaseofthesamesex,ofcourse。

Wewillfirstconsidertheshortvestibule,atthemostlargeenoughtoreceivetheplugwithwhichtheOsmiawillcloseupthelodging。

Thereisthennothingatherdisposalexceptthecellproper,aspaciousapartmentinwhichoneoftheOsmia\'sfemaleswillfindampleaccommodation,forsheismuchsmallerthantheoriginaloccupantofthechamber,nomatterthesex;butthereisnotroomfortwococoonsatatime,especiallyinviewofthespacetakenupbytheinterveningpartition。Well,inthoselarge,well—builtchambers,formerlythehomesofChalicodomae,theOsmiasettlesfemalesandnonebutfemales。

Letusnowconsiderthelongvestibule。Here,apartitionisconstructed,encroachingslightlyonthecellproper,andtheresidenceisdividedintotwounequalstoreys,alargeroombelow,housingafemale,andanarrowcabinabove,containingamale。

Whenthelengthofthevestibulepermits,allowingforthespacerequiredbytheouterstopper,athirdstoreyisbuilt,smallerthanthesecond;andanothermaleislodgedinthiscrampedcorner。InthiswaytheoldnestoftheMason—beeofthePebblesiscolonized,cellaftercell,byasinglemother。

TheOsmia,aswesee,isveryfrugalofthelodgingthathasfallentohershare;shemakesthebestpossibleuseofit,givingtothefemalesthespaciouschambersoftheMason—beeandtothemalesthenarrowvestibules,subdividedintostoreyswhenthisisfeasible。

Economyofspaceisthechiefconsideration,sinceherstay—at—hometastesdonotallowhertoindulgeindistantquests。Shehastoemploythesitewhichchanceplacesatherdisposaljustasitis,nowforamaleandnowforafemale。Hereweseedisplayed,moreclearlythanever,herpowerofdecidingthesexoftheegg,inordertoadaptitjudiciouslytotheconditionsofthehouse—roomavailable。

IhadofferedatthesametimetotheOsmiaeinmystudysomeoldnestsoftheMason—beeoftheShrubs,whichareclayspheroidswithcylindricalcavitiesinthem。Thesecavitiesareformed,asintheoldnestsoftheMason—beeofthePebbles,ofthecellproperlyso—

calledandoftheexit—waywhichtheperfectinsectcutthroughtheoutercoatingatthetimeofitsdeliverance。Theirdiameterisaboutsevenmillimetres（。273inch。——Translator\'sNote。）;theirdepthatthecentreoftheheapis23millimetres（。897inch。——Translator\'sNote。）;andattheedgeaverages14millimetres（。546inch。——

Translator\'sNote。）

ThedeepcentralcellsreceiveonlythefemalesoftheOsmia;

sometimeseventhetwosexestogether,withapartitioninthemiddle,thefemaleoccupyingthelowerandthemaletheupperstorey。

True,insuchcaseseconomyofspaceisstrainedtotheutmost,theapartmentsprovidedbytheMason—beeoftheShrubsbeingverysmallasitis,despitetheirentrance—halls。Lastly,thedeepercavitiesonthecircumferenceareallottedtofemalesandtheshallowertomales。

Iwilladdthatasinglemotherpeopleseachnestandalsothatsheproceedsfromcelltocellwithouttroublingtoascertainthedepth。

Shegoesfromthecentretotheedges,fromtheedgestothecentre,fromadeepcavitytoashallowcavityandviceversa,whichshewouldnotdoifthesexesweretofollowuponeachotherinasettledorder。Forgreatercertainty,Inumberedthecellsofonenestaseachofthemwasclosed。Onopeningthemlater,Iwasabletoseethatthesexeswerenotsubjectedtoachronologicalarrangement。

Femalesweresucceededbymalesandthesebyfemaleswithoutitsbeingpossibleformetomakeoutanyregularsequence。Only——andthisistheessentialpoint——thedeepcavitieswereallottedtothefemalesandtheshallowonestothemales。

WeknowthattheThree—hornedOsmiapreferstohauntthehabitationsoftheBeeswhonidifyinpopulouscolonies,suchastheMason—beeoftheShedsandtheHairy—footedAnthophora。Exercisingtheverygreatestcare,IbrokeupsomegreatlumpsofearthremovedfromthebanksinhabitedbytheAnthophoraandsenttomefromCarpentrasbymydearfriendandpupilM。Devillario。Iexaminedthemconscientiouslyinthequietofmystudy。IfoundtheOsmia\'scocoonsarrangedinshortseries,inveryirregularpassages,theoriginalworkofwhichisduetotheAnthophora。Touchedupafterwards,madelargerorsmaller,lengthenedorshortened,intersectedwithanetworkofcrossingsbythenumerousgenerationsthathadsucceededoneanotherinthesamecity,theyformedaninextricablelabyrinth。

Sometimesthesecorridorsdidnotcommunicatewithanyadjoiningapartment;sometimestheygaveaccesstothespaciouschamberoftheAnthophora,whichcouldberecognized,inspiteofitsage,byitsovalshapeanditscoatingofglazedstucco。Inthelattercase,thebottomcell,whichonceconstituted,byitself,thechamberoftheAnthophora,wasalwaysoccupiedbyafemaleOsmia。Beyondit,inthenarrowcorridor,amalewaslodged,notseldomtwo,oreventhree。Ofcourse,claypartitions,theworkoftheOsmia,separatedthedifferentinhabitants,eachofwhomhadhisownstorey,hisownclosedcell。

Whentheaccommodationconsistedofnomorethanasimplecylinder,withnostate—bedroomattheendofit——abedroomalwaysreservedforafemale——thecontentsvariedwiththediameterofthecylinder。Theseries,ofwhichthelongestwereseriesoffour,included,withawiderdiameter,firstoneortwofemales,thenoneortwomales。Italsohappened,thoughrarely,thattheserieswasreversed,thatistosay,itbeganwithmalesandendedwithfemales。Lastly,therewereagoodmanyisolatedcocoons,ofonesexortheother。WhenthecocoonwasaloneandoccupiedtheAnthophora\'scell,itinvariablybelongedtoafemale。

IhaveobservedthesamethinginthenestsoftheMason—beeoftheSheds,butnotsoeasily。Theseriesareshorterhere,becausetheMason—beedoesnotboregalleriesbutbuildscelluponcell。Theworkofthewholeswarmthusformsastratumofcellsthatgrowsthickerfromyeartoyear。ThecorridorsoccupiedbytheOsmiaaretheholeswhichtheMason—beeduginordertoreachdaylightfromthedeeplayers。Intheseshortseries,bothsexesareusuallypresent;and,iftheMason—bee\'schamberisattheendofthepassage,itisinhabitedbyafemaleOsmia。

WecomebacktowhattheshorttubesandtheoldnestsoftheMason—

beeofthePebbleshavealreadytaughtus。TheOsmiawho,intubesofsufficientlength,dividesherwholelayingintoacontinuoussequenceoffemalesandacontinuoussequenceofmales,nowbreaksitupintoshortseriesinwhichbothsexesarepresent。Sheadaptshersectionallayingstotheexigenciesofachancelodging;shealwaysplacesafemaleinthesumptuouschamberwhichtheMason—beeortheAnthophoraoccupiedoriginally。

FactsevenmorestrikingaresuppliedbytheoldnestsoftheMaskedAnthophora（A。personata,ILLIG。）,oldnestswhichIhaveseenutilizedbytheHornedOsmiaandtheThree—hornedOsmiaatthesametime。Lessfrequently,thesamenestsserveforLatreille\'sOsmia。

LetusfirstdescribetheMaskedAnthophora\'snests。

Inasteepbankofsandyclay,wefindasetofround,wide—openholes。Therearegenerallyonlyafewofthem,eachabouthalfaninchindiameter。Theyaretheentrance—doorsleadingtotheAnthophora\'sabode,doorsalwaysleftopen,evenafterthebuildingisfinished。Eachofthemgivesaccesstoashortpassage,sometimesstraight,sometimeswinding,nearlyhorizontal,polishedwithminutecareandvarnishedwithasortofwhiteglaze。Itlooksasifithadreceivedathincoatofwhitewash。Ontheinnersurfaceofthispassage,inthethicknessoftheearthybank,spaciousovalnicheshavebeenexcavated,communicatingwiththecorridorbymeansofanarrowbottle—neck,whichisclosed,whentheworkisdone,withasubstantialmortarstopper。TheAnthophorapolishestheoutsideofthisstoppersowell,smoothsitssurfacesoperfectly,bringingittothesamelevelasthatofthepassage,issocarefultogiveitthewhitetintoftherestofthewallthat,whenthejobisfinished,itbecomesabsolutelyimpossibletodistinguishtheentrance—doorcorrespondingwitheachcell。

Thecellisanovalcavitydugintheearthymass。Thewallhasthesamepolish,thesamechalkywhitenessasthegeneralpassage。ButtheAnthophoradoesnotlimitherselftodiggingovalniches:tomakeherworkmoresolid,shepoursoverthewallsofthechamberasalivaryliquidwhichnotonlywhitensandvarnishesbutalsopenetratestoadepthofsomemillimetresintothesandyearth,whichitturnsintoahardcement。Asimilarprecautionistakenwiththepassage;andthereforethewholeisasolidpieceofworkcapableofremaininginexcellentconditionforyears。

Moreover,thankstothewallhardenedbythesalivaryfluid,thestructurecanberemovedfromitsmatrixbychippingitcarefullyaway。Wethusobtain,atleastinfragments,aserpentinetubefromwhichhangsasingleordoublerowofovalnodulesthatlooklikelargegrapesdrawnoutlengthwise。Eachofthesenodulesisacell,theentrancetowhich,carefullyhidden,opensintothetubeorpassage。Whenshewishestoleavehercell,inthespring,theAnthophoradestroysthemortardiskthatclosesthejarandthusreachesthegeneralcorridor,whichisquiteopentotheouterair。

Theabandonednestprovidesaseriesofpear—shapedcavities,ofwhichthedistendedpartistheoldcellandthecontractedparttheexit—neck,ridofitsstopper。

Thesepear—shapedhollowsformsplendidlodgings,impregnablestrongholds,inwhichtheOsmiaefindasafeandcommodiousretreatfortheirfamilies。TheHornedOsmiaandtheThree—hornedOsmiaestablishthemselvesthereatthesametime。Althoughitisalittletoolargeforher,Latrielle\'sOsmiaalsoappearsverywellsatisfiedwithit。

Ihaveexaminedsomefortyofthesuperbcellsutilizedbyeachofthefirsttwo。Thegreatmajorityaredividedintotwostoreysbymeansofatransversalpartition。ThelowerstoreyincludesthelargerportionoftheAnthophora\'scell;theupperstoreyincludestherestofthecellandalittleofthebottle—neckthatsurmountsit。Thetwo—roomeddwellingisclosed,inthepassage,byashapeless,bulkymassofdriedmud。WhataclumsyartisttheOsmiais,comparedwiththeAnthophora！AgainsttheexquisiteworkoftheAnthophora,partitionandplugstrikeanoteashideouslyincongruousasalumpofdirtonpolishedmarble。

Thetwoapartmentsthusobtainedareofaveryunequalcapacity,whichatoncestrikestheobserver。Imeasuredthemwithmyfive—

millimetretube。Onanaverage,thebottomoneisrepresentedbyacolumnofsand50millimetresdeep（1。95inches。——Translator\'sNote。）

andthetoponebyacolumnof15millimetres（。585inch。——

Translator\'sNote。）。Theholding—capacityoftheoneisthereforeaboutthreetimesaslargeasthatoftheother。Thecocoonsenclosedpresentthesamedisparity。Thebottomoneisbig,thetoponesmall。

Lastly,theloweronebelongstoafemaleOsmiaandtheuppertoamaleOsmia。

Occasionallythelengthofthebottle—neckallowsofafresharrangementandthecavityisdividedintothreestoreys。Thebottomone,whichisalwaysthemostspacious,containsafemale;thetwoabove,bothsmallerthanthefirstandonesmallerthantheother,containmales。

Letuskeeptothefirstcase,whichisalwaysthemostfrequent。TheOsmiaisinthepresenceofoneofthesepear—shapedhollows。Itisafindthatmustbeemployedtothebestadvantage:aprizeofthissortisrareandfallsonlytofortune\'sfavourites。Tolodgetwofemalesinitatonceisimpossible;thereisnotsufficientroom。Tolodgetwomalesinitwouldbeunduegenerositytoasexthatisentitledtobutthesmallestconsideration。Besides,thetwosexesmustberepresentedinalmostequalnumbers。TheOsmiadecidesupononefemale,whoseportionshallbethebetterroom,thelowerone,whichislarger,better—protectedandmorenicelypolished,andonemale,whoseportionshallbetheupperstorey,acrampedattic,unevenandruggedinthepartwhichencroachesonthebottle—neck。

Thisdecisionisprovedbynumerousundeniablefacts。BothOsmiaethereforecanchoosethesexoftheeggabouttobelaid,seeingthattheyarenowbreakingupthelayingintogroupsoftwo,afemaleandamale,asrequiredbytheconditionsofthelodging。

IhaveonlyoncefoundLatreille\'sOsmiaestablishedinthenestoftheMaskedAnthophora。Shehadoccupiedbutasmallnumberofcells,becausetheotherswerenotfree,beinginhabitedbytheAnthophora。

Thecellsinquestionweredividedintothreestoreysbypartitionsofgreenmortar;thelowerstoreywasoccupiedbyafemale,thetwoothersbymales,withsmallercocoons。

Icametoanevenmoreremarkableexample。TwoAnthidiaofmydistrict,A。septemdentatum,LATR。,andA。bellicosum,LEP。,adoptasthehomeoftheiroffspringtheemptyshellsofdifferentsnails:

Helixaspersa,H。algira,H。nemoralis,H。caespitum。Thefirst—

named,theCommonSnail,isthemostoftenused,underthestone—

heapsandinthecrevicesofoldwalls。BothAnthidiacolonizeonlythesecondwhorlofthespiral。Thecentralpartistoosmallandremainsunoccupied。Evensowiththefrontwhorl,thelargest,whichisleftcompletelyempty,somuchsothat,onlookingthroughtheopening,itisimpossibletotellwhethertheshelldoesordoesnotcontaintheBee\'snest。Wehavetobreakthislastwhorlifwewouldperceivethecuriousnesttuckedawayinthespiral。

Wethenfindfirstatransversalpartition,formedoftinybitsofgravelcementedbyaputtymadefromresin,whichiscollectedinfreshdropsfromtheoxycedrusandtheAleppopine。Beyondthisisastoutbarricademadeupofrubbishofallkinds:bitsofgravel,scrapsofearth,juniper—needles,thecatkinsoftheconifers,smallshells,driedexcretionsofSnails。Nextcomeapartitionofpureresin,alargecocooninaroomychamber,asecondpartitionofpureresinand,lastly,asmallercocooninanarrowchamber。Theinequalityofthetwocellsisthenecessaryconsequenceoftheshapeoftheshell,whoseinnerspacegainsrapidlyinwidthasthespiralgetsnearertotheorifice。Thus,bythemeregeneralarrangementofthehomeandwithoutanyworkontheBee\'spartbeyondsomeslenderpartitions,alargeroomismarkedoutinfrontandamuchsmallerroomattheback。

Byaveryremarkableexception,whichIhavementionedcasuallyelsewhere,themalesofthegenusAnthidiumaregenerallylargerthanthefemales;andthisisthecasewiththetwospeciesinparticularthatdividetheSnail\'sspiralwithresinpartitions。Icollectedsomedozensofnestsofbothspecies。Inatleasthalfthecases,thetwosexeswerepresenttogether;thefemale,thesmaller,occupiedthefrontcellandthemale,thebigger,thebackcell。Othercells,whichweresmallerortoomuchobstructedatthebackbythedried—upremainsoftheMollusc,containedonlyonecell,occupiedatonetimebyafemaleandatanotherbyamale。Afew,lastly,hadbothcellsinhabitednowbytwomalesandnowbytwofemales。Themostfrequentarrangementwasthesimultaneouspresenceofbothsexes,withthefemaleinfrontandthemalebehind。TheAnthidiawhomakeresin—

doughandliveinSnail—shellscanthereforealternatethesexesregularlytomeettheexigenciesofthespiraldwelling—house。

OnemorethingandIhavedone。Myapparatusofreeds,fixedagainstthewallsofthegarden,suppliedmewitharemarkablenestoftheHornedOsmia。Thenestisestablishedinabitofreed11millimetreswideinside。（。429inch——Translator\'sNote。）Itcomprisesthirteencellsandoccupiesonlyhalfthecylinder,althoughtheorificeispluggedwiththeusualstopper。Thelayingthereforeseemsheretobecomplete。

Well,thislayingisarrangedinamostsingularfashion。Thereisfirst,atasuitabledistancefromthebottomorthenodeofthereed,atransversalpartition,perpendiculartotheaxisofthetube。

Thismarksoffacellofunusualsize,inwhichafemaleislodged。

Afterthat,inviewoftheexcessivewidthofthetunnel,whichistoogreatforaseriesinsinglefile,theOsmiaappearstoalterhermind。Shethereforebuildsapartitionperpendiculartothetransversalpartitionwhichshehasjustconstructedandthusdividesthesecondstoreyintotworooms,alargerroom,inwhichshelodgesafemale,andasmaller,inwhichshelodgesamale。Shenextbuildsasecondtransversalpartitionandasecondlongitudinalpartitionperpendiculartoit。Theseoncemoregivetwounequalchambers,stockedlikewise,thelargeonewithafemale,thesmalleronewithamale。

>Fromthisthirdstoreyonwards,theOsmiaabandonsgeometricalaccuracy;thearchitectseemstobealittleoutinherreckoning。

Thetransversalpartitionsbecomemoreandmoreslantingandtheworkgrowsirregular,butalwayswithasprinklingoflargechambersforthefemalesandsmallchambersforthemales。Threefemalesandtwomalesarehousedinthisway,thesexesalternating。