The Larva and the Nymph 103 



with vigorous jerks the joint of the neck and 

 that of the peduncle connecting the abdomen 

 and the thorax. At last its efforts are crowned 

 with success ; and, after a quarter of an hour 

 of these rough gymnastics, the scabbard, tugged 

 in every direction, rips open at the neck, at 

 the point where the legs are attached and near 

 the peduncle of the abdomen, in short, wherever 

 the mobility of the parts has permitted any 

 violent dislocation to take place. 



All these rents in the veil that is being cast 

 result in a number of irregular shreds, whereof 

 the largest envelops the abdomen and runs up 

 the back of the thorax. To this shred belong 

 the wing-cases. A second shred covers the 

 head. Lastly, each leg has its own sheath, 

 more or less badly treated near the base. The 

 large shred, which in itself forms the best part 

 of the wrapper, is thrown off by means of 

 alternate contractions and expansions of the 

 abdomen. By this mechanical process it is 

 slowly forced backwards, where it ends by 

 forming a little pellet that for some time re- 

 mains fastened to the insect by the tracheal 

 gills. The Sphex then once more becomes 

 motionless ; and the operation is over. How- 

 ever, the head, antennae and legs are still more 

 or less veiled. It is evident that the legs in 

 particular cannot be freed all in one piece, 



