ItmayhappenthattheOsmia\'spatienceisinvainandthatthebarricadethatblocksthewayneverdisappearsatall。Sometimes,theegginacelldoesnotmature;andtheunconsumedprovisionsdryupandbecomeacompact,sticky,mildewedplug,throughwhichtheoccupantsofthefloorsbelowcouldneverclearthemselvesapassage。
Sometimes,again,agrubdiesinitscocoon;andthecradleofthedeceased,nowturnedintoacoffin,formsaneverlastingobstacle。
Howshalltheinsectcopewithsuchgravecircumstances？
Amongthemanybramble—stumpswhichIhavecollected,somefewhavepresentedaremarkablepeculiarity。Inadditiontotheorificeatthetop,theyhadatthesideoneandsometimestworoundaperturesthatlookedasthoughtheyhadbeenpunchedoutwithaninstrument。Onopeningthesestalks,whichwereold,desertednests,Idiscoveredthecauseoftheseveryexceptionalwindows。Aboveeachofthemwasacellfullofmouldyhoney。Theegghadperishedandtheprovisionsremaineduntouched:hencetheimpossibilityofgettingoutbytheordinaryroad。Walledinbytheunsurmountableobstacle,theOsmiaonthefloorbelowhadcontrivedanoutletthroughthesideoftheshaft;andthoseinthelowerstoreyshadbenefitedbythisingeniousinnovation。Theusualdoorbeinginaccessible,aside—windowhadbeenopenedbymeansoftheinsect\'sjaws。Thecocoons,torn,butstillinpositioninthelowerrooms,leftnodoubtastothiseccentricmodeofexit。Thesamefact,moreover,wasrepeated,inseveralbramble—
stumps,inthecaseofOsmiatridentata;itwaslikewiserepeatedinthecaseofAnthidiumscapulare。Theobservationwasworthconfirmingbyexperiment。