252 



INSECT TRANSFORMATION 



ground that the oldest larvae must have lived in concealed 

 situations where burrowing or mining was necessary a manner 

 of life to which the caterpillar is often admirably adapted. 

 Among the Lepidoptera, whereof the caterpillar is most 

 especially the characteristic larval form, we find that this 

 habit of concealment- mining, burrowing, case-forming is 

 particularly distinctive of the families of lower grade, such as 

 swift-moths, clothes-moths, the goat-moth family, and the 

 clearwings ; while the caterpillars of the more highly-organized 

 families, like the owl-moths, " loopers ", and butterflies, usually 



FIG. 121. 



a, Caterpillar of Swift Moth (Ht'^ialuf) (side view), x 2. 6, third abdominal 

 segment of Hef>ici!ns larva ; c, of Pynilid larva ; d, of " Tiger" (Arctiid) 

 larva. x 3. In part after Packard, Mem. Nat. Acad., Sci. VII .ni'l 

 Dyar, Ann. N.Y. Acad. Set. VII I. 



feed openly exposed on leaves. But when the details of the 

 cuticle and armature of a series of lepidopteran caterpillars 

 are studied, 1 it is seen that in their relatively longer legs, more 

 numerous and larger bristle-bearing plates, and well-developed 

 prothoracic and post-abdominal terga, the caterpillars (Fig. 

 121 a b) of these primitive moths approach the active well- 

 armoured beetle larvae, while among the highly-developed 

 Lepidoptera the caterpillar either becomes superficially smooth 

 with a very feebly-developed, bristly armature (c), as with 

 most owl-moths and " loopers ", or it develops a dense, 

 close covering of protective hairs or spines (d) in connexion 



1 H. G. Dyar: "A Classification of Lepidopterous Larvae". Ann. 

 New York Acad. Sci., VIII. 1893. T. A. Chapman : " Some Notes on the 

 Micro-Lepidoptera whose Larvae are external feeders, and chieily on the early 

 Stages of Eriocephala calthella ". Trans. Entom. Soc. 1894. 



