16 NEUROPTERA. 



cover the wings of the Lepidoptera. These 

 hairs, where they exist, are placed more par- 

 ticularly along the nerves, which, by their dis- 

 position, give that peculiar reticulated or net- 

 work appearance to the wings. It is well to 

 observe the arrangement of the principal nerves, 

 which pass from the base to the extremity of 

 the wings, since they serve to mark the genera, 

 being constantly disposed in the same manner, 

 in the species of the same genus. This obser- 

 vation applies with equal force to the trans- 

 versal nerves. They exhibit differences as re- 

 markable, and as constant with respect to the 

 genera, as those which run in a longitudinal 

 direction. 



