HABITATIONS OF INSECTS. 287 



work into portions of an ellipse, into ovals or circles, accurately accommo- 

 dating the dimensions of the several pieces of each figure to each other. 

 What other architect could carry impressed upon the tablet of his memory 

 the entire idea of the edifice which he has to erect, and, destitute of 

 square or plumb-line, cut out his materials in their exact dimensions with- 

 out making a single mistake? Yet this is what our little bee invariably 

 does. So far are human art and reason excelled by the teaching of tne 

 Almighty.^ 



Other insects besides bees construct habitations of different kinds for 

 their young, as various species of burrowing wasps (^Fossores), Gcotriipes, 

 &.C., which deposit their eggs in cylindrical excavations that become the 

 abode of the future larva;. In the procedures of most of these nothing 

 worth particularizing occurs; but one species, called by Reaumur the 

 mason-wasp (^Odynerus murarius), referred to in a former letter, works 

 upon so singular a plan, that it would be improper to pass it over in 

 silence, especially as these nests may be found in this country in most 

 sandy banks exposed to the sun. This insect bores a cylindrical cavity 

 from two to three inches deep, in hard sand which its mandibles alone 

 would be scarcely capable of penetrating, were it not provided with a 

 slightly glutinous liquor which it pours out of its mouth, that, like the 

 vinegar with which Hannibal softened the Alps, acts upon the cement of 

 the sand, and renders the separation of the grains easy to the double pick- 

 axe with which our little pioneer is furnished. But the most remarkable 

 circumstance is the mode in which it disposes of the excavated materials. 

 Instead of throwing them at random on a heap, it carefully forms them 

 into little oblong pellets, and arranges them round the entrance of the hole 

 so as to form a tunnel, which, when the excavation is completed, is often 

 not less than two or three inches in length. For the greater part of its 

 height this tunnel is upright, but towards the top it bends into a curve, 

 always, however, retaining its cylindrical form. The little masses are so 

 attached to each other in this cylinder as to leave numerous vacuities 

 between them, which give it the appearance of filagree-work. You will 

 readily divine that the excavated hole is intended for the reception of an 

 egg, but for what purpose the external tunnel is meant is not so apparent. 

 One use, and perhaps the most important, would seem to be to prevent 

 the incursions of the artful Ichneumons, Chrysidce, he, which are ever 

 on the watch to insinuate their parasitic young into the nests of other 

 insects : it may render their access to the nest more difficult; they may 

 dread to enter into so long and dark a defile. I have seen, however, 

 more than once a Chrysis come out of these tunnels. That its use is only 

 temporary is plain from the circumstance that the insect employs the 

 whole fabric, when its egg is laid and store of fruit procured, in filling up 

 the remaining vacuity of the hole ; taking down the pellets, which are 

 very conveniently at hand, and placing them in it until the entrance is 

 filled." — Latreille informs us that a nearly similar tunnel, but composed of 

 grains of earth, is built at the entrance of its cell by a bee of his family 

 of pioneers.^ 



The habitations hitherto described are used simply as an abode for the 



' Reaurn. vi. 971—24. Mm Ap. Angl. i. 157. Apis. **. c. 2. a. 



» Reaum. vi. 251—257. t. ixvi. f. 1. » Latr. Fourmis, 419. 



