424 TRANSFORMATIONS OF INSECTS. 



the antennae. The head is carefully withdrawn through the opening 

 in its covering, and with it the antennae and parts of the mouth, 

 and afterwards the anterior segments and single pair of legs. 

 The first and apparently most difficult part of the shedding of 

 the skin is its detachment from the posterior segments of the 

 body, and from the interior of the large intestine. To effect this 

 the animal, which has been previously lying coiled up in a circular 

 form, first straightens its whole body ; it then forcibly contracts and 

 shortens itself, especially at the posterior part, and by this means be- 

 comes greatly enlarged in bulk at its middle portion, but smaller at 

 its extremities. During these efforts, which are some of the most 

 powerful it is able to make, the skin becomes loosened from its 

 posterior parts, and while still contracting its segments, the anal 

 extremities, and with it the entire lining of the large intestine, be- 

 come completely detached, and from these it gently withdraws 

 itself within the old skin, in which the body is encased, as from the 

 finger of a glove. This is precisely what takes place in the shed- 

 ding of the skin in true insects. Having effected this part of its 

 labour, all the posterior segments are again shortened ; the animal 

 once more disposes itself in a circular form, and after repeated 

 exertions, succeeds in bursting the tegument of the head in the part 

 just described. As in the case of the true insects, the young Julus 

 entirely empties its alimentary canal and ceases to eat for one or 

 two days preceding each skin shedding. When examined imme- 

 diately before the change there are no other symptoms of new legs 

 than slight elevations of the skin, and this perhaps accounts for 

 the length of time occupied in the change, the new legs requiring 

 time for further development before the old skin is thrown off. 



Having cast its skin, and thus attained the fifth period of 

 development, the young Jidiis has three ocelli on each side of 

 the head, seven joints to the antennae, thirty-four legs, and twenty- 

 one segments to its body. 



The Jiiliis changed its skin again on the sixty-third day, and 

 entered its sixth period of development. It then had acquired 

 twenty-seven segments to its body, which had greatly increased 

 in size, and was of a brown tint. There were six distinct ocelli 

 on each side of the head, and there were altogether fifty-eight legs. 



The Chilopoda, which have less numerous legs, appear to 



