The Sitares 



forms the armour of the hinder-part. If we 

 examine attentively the surface of the ver- 

 tical wall which contains the various nests, it 

 will not be long before we discover nymphs 

 like those which we have been describing, 

 with one extremity held in a gallery of their 

 own diameter, while the fore-part projects 

 freely into the air. But these nymphs are 

 reduced to their cast skins, along the back 

 and head of which runs a long slit through 

 which the perfect insect has escaped. The 

 purpose of the nymph's powerful weapons is 

 thus made manifest: it is the nymph that has 

 to rend the tough cocoon which imprisons it, 

 to excavate the tightly-packed soil in which 

 it is buried, to dig a gallery with its six- 

 pointed snout and thus to bring to the light 

 the perfect insect, which apparently is in- 

 capable of performing these strenuous tasks 

 for itself. 



And in fact these nymphs, taken in their 

 cocoons, have in a few days' time given me a 

 feeble Fly (Anthrax sinuata) who is quite in- 

 capable of piercing the cocoon and still more 

 of making her exit through a soil which I 

 cannot easily break up with my pick. Al- 

 though similar facts abound in insect history, 

 we always notice them with a lively interest. 

 They tell us of an incomprehensible power 



35 



