TWO YOUNG NATURALISTS. 107 



ascertained, but which have been supposed to be 

 biliary vessels. 



" This is really superb," said the Parisian, as he 

 shifted the preparation from place to place under the 

 object glass, so as to seize all its details. "But before 

 commencing the study of the internal anatomy of 

 insects, I think it will be advisable to learn to dis- 

 tinguish them from one another ; for without some 

 sort of classification this must be, as you say, by no 



HEAD -LOUSE, MUCH MAGNIFIED. 



means an easy affair, seeing how numerous are their 

 kinds." 



" Numerous indeed. Of all animals they are by far 

 the most numerous ; of ants alone there are known 

 about fifteen hundred different kinds. And so, in 

 order to keep from being lost in such a labyrinth, 

 several divisions have been adopted, and eight diffe- 

 rent orders are recognised, based on the number and 

 nature of the wings. They are 



"1. Aptera, destitute of wings. 



