HABITATIONS OF INSECTS. 



373 



tified might defy the attacks of every insect marauder. Yet 

 an Ichneumon and a beetle (Clerus apiarius) both contrive 

 to introduce their eggs into the cells, and the larvae proceed- 

 ing from them devour their inhabitants. ^ 



Other bees of the same group with that last described use 

 different materials in the construction of their nests. Some 

 employ fine earth made into a kind of mortar with gluten. 

 Another (^Osmia'^ ccerulescens), as we learn from De Greer, 

 forms its nest of argillaceous earth mixed with chalk, upon 

 stone walls, and sometimes probably nidificates in chalk-pits. 

 O. hicornis, according to Reaumur, selects the hollows of 

 large stones for the site of its dwelling ; but in England 

 seems to prefer rotten posts and palings, in which it bores 

 upwards, and then forms the partitions of its cells of clay 

 and sand glued together. One species of this genus ( O. gaU 

 larum) saves itself trouble by placing its cells in an abandoned 

 gall of the oak, and others select, with the like object, empty 

 snail-shells.^ One remarkable peculiarity of some of these 

 insects is, that they conceal the place where their cells are 

 situated with some extraneous material. Thus O. gallarum 

 hides the galls it has adopted by glueing round them oak 

 leaves, and a species which M. Goureau conceives to be O. 

 bicolor employed a whole day in arranging over the mouth 

 (as he supposes) of its cell pieces of grass about two inches 

 long, in a conical or tent-like form'*; and that this species 

 employs this material for some purpose connected with its 

 nest is confirmed by Mr. Thwaites, who observed a female 

 for a considerable time fetching similar pieces of grass, and 

 laying them over a snail-shell, where he had every reason to 



1 Reaum. vi. 57 — 88. Mon. Ap. Angl.x. 119. According to M. Goureau, 

 Eeaumur and succeeding entomologists have always confounded under Megaehile 

 muraria two very distinct species. The first, which he considers the true one, 

 constructs its nest in April, — selecting the exposed surface of a rock, stone, or 

 wall (not an angle), and preferring solitary places distant both from the noise of 

 the abode of man and from the habitations of its own tribe; whereas the other, 

 which does not begin its nest till the end of May or beginning of June, always 

 places it in the angle of some wall or pilaster, &c. of a building, seeming to pre- 

 fer inhabited houses and to be near others of its species, close to whose nests it 

 often places its own. {Ann. Soc. Ent.'de France, ix. 118.) 



2 Apis. **. c. 2. 5. K. 



3 Westwood, Mod. Class, of Ins. ii. 274. 

 Ann. Soc. Ent. de France, ix. 1 23. 



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