232 



LEP1DOPTEBA. 



168 - 



etc., giving us an unfailing test of the difference in rank of the 



two suborders. In their habits and transformations, and 



in their external 

 anatomy, the Lep- 

 idoptera vary less 

 than other insects. 

 The Lepidop- 

 tera, while in the 

 perfect state, can 

 be scarcely said to 

 walk much, com- 

 pared with beetles 

 and other walking 



insects, the legs being only used to support them while at rest, 



and not for locomotion. They move almost entirely by their 



broad wings, which 



with them are more 



highly specialized 



than in other in- 



sects. Their fore 



wings are usually 



triangular in form, 



while their hind 



wings are some- Fi s- 169 - 



what square or rounded. The anterior wings are the most 



typical in form and venation. 



The surface, from the costa to the inner edge, may be 



A B C 



Fig. 171. 



divided into three areas, the costal, median, and internal. 

 There are five principal veins : the costal and subcostal are 



