INSECTA. 



301 



length (fig. 137, B), getting its body from its now useless cover- 

 ing, it becomes entirely free. The wings, before soft and crumpled, 

 slowly expand (Jig. 137, c) ; the nervures harden, the extended 

 membranes dry, and Fig. 137. 



in a short time the 

 winged tyrant of the 

 insect world (fig. 

 103) commences his 

 aerial career. 



(346.) A strong 

 argument in favour 

 of the above views 

 concerning the pro- 

 duction of successive 

 skins from the der- 

 mis, is derived from 

 the phenomena at- 

 tending the cure of 

 wounds in insects. 

 If a perfect insect 

 be wounded, the 

 wound is never heal- 

 ed at all ; and, if a 

 larva or pupa is 

 similarly injured, the 

 wound remains un- 

 cicatrised until the 

 next moult, when 

 the newly formed in- 

 tegument is found 

 to exhibit no traces 

 of the injury : the 

 secreted and extra- 

 vascular cuticle can 

 not cicatrise ; but the 



living and vascular dermis is not only able to repair injuries in- 

 flicted upon itself, but, in secreting the next investment, to obliter- 

 ate all indications of their occurrence. 



(347.) The changes above described are produced by the pro- 

 gressive developement of the dermic or tegumentary system ; the 

 parts of which, as we have already seen, becoming strengthened and 



