44S HABITATIONS OF INSECTS. 



lindrical form. The little masses are so attached to 

 each other in this cylinder, as to leave numerous va- 

 cuities between them, which give it the appearance of 

 filagfree-work. You will readih divine that the exca- 

 vated hole is intended for the reception of an e^"^, but 

 for what purpose the external tunnel is meant is not 

 so apparent. One use, and perhaps the most impor- 

 tant, would seem to be to prevent the incursions of the 

 artful Ichneumons, Chri/sidce, &c. wliich 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 circum- 

 stance that the insect employs the whole fabric, when 

 its eg^ is laid and store of food procured, in filling up 

 the remaining vacuity of the hole ; taking down the pel- 

 lets, which are very conveniently at hand, and placing 

 them in it until the entrance is filled''. — Latreille in- 

 forms 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^. 



Under this head, too, may be most conveniently ar- 

 ranged the very singular habitations of the larvae of the 

 Linnaean genus C?/mps, the gall-fly, though they can 

 with no propriety be said to be constructed by the mo- 

 ther, who, provided with an instrument as potent as 

 an enchanter's wand, has but to pierce the site of the 

 foundation, and commodious apartments, as if by magic, 

 spring up and surround the germe of her future de- 



' ReaUDO. vi. 251-7. i. xxvi. /.I. " Latr. Fourmh, 419. 



