36o The Pedigree of Insects 



morphic insects, since the discovery of elytra in the 

 Carboniferous rocks of Germany shows that the Cole- 

 optera were already differentiated in later Palaeozoic 

 times. And in the Trias of Switzerland undoubted 

 remains of weevils have been found, proving that 

 a family with eruciform larvee had arisen in the earliest 

 of the Secondary periods. The Chrysomelidje and 

 Buprestidse also can be traced back to the Trias and 

 the Carabidae, Elateridae, Cerambycids and Scarabaeidae 

 to the Lias (203). Clearly, therefore, the beetles 

 had not only become differentiated as an order, but 

 were already being specialised into the principal exist- 

 ing families at the close of the Primary epoch. The 

 Neuroptera as we know them to-day cannot be traced 

 back as far as the Beetles, but remains of Sialidae and 

 Panorpidse occur in Liassic, and of Chrysopidse in 

 Oolitic rocks. 



Trichoptera and Lepidoptera. — Reference has 

 already been made to the close relationship between 

 the Trichoptera and the Lepidoptera (Chapter III, pp. 

 156-8), the lowest family (Microptcrygida?) referred 

 to the latter order resembling Caddis-flies in the 

 possession of functional mandibles in the pupa, and 

 Jaciniae in the first maxillae of the imago. The 

 pupae of Trichoptera are free, and become active in 

 preparation for the final change, while among the 

 Lepidoptera a transition from this state of things can 

 be traced as we ascend in the scale of the families to 

 an obtect pupa with two or three abdominal segments 

 alone capable of motion. The larvae in both orders 

 are eruciform, but while those of Caddis-flies are 

 almost all aquatic, those of Moths and Butterflies 

 are, almost without exception, arboreal, and as a 

 necessary adaptation for life on twigs and branches 

 of trees and herbs, are provided with clasping pro- 

 legs on the hind-body. Turning to the wing-structure 



