4 POPULAR ENTOMOLOGY. 



larvae are of various forms, and are divided into two principal 

 classes those having a distinct scaly head, including many 

 of our principal insects, and those without a distinct head, 

 as the majority of the two-winged Flies ; the minor dis- 

 tinctions depend principally on the number of the legs and 

 prolegs, but for these the student must refer to larger works. 

 Having attained its full size after several times changing the 

 skin, the larva undergoes its final and most important trans- 

 formation, appearing in quite a different shape, that of the 

 pupa, during the period of which it remains more or less 

 inactive, and would be liable to destruction were it not for 

 the admirable instinct shown by the larva in preparing for 

 the new state of existence to which it is destined. Here again 

 the distinctions are too multiplied to be fully entered into 

 in so slight a sketch as the present, though the whole may 

 be classed under two headsthose whose transformation is 

 partial, and those in which it is complete. Linnaeus divided 

 them into five kinds, as follows : 



Pupa completa, active, with all the parts of the perfect 

 insect: example, Aranea, the Spider. 



Pupa semi-completa, active, resembling the parent, but 

 having only the rudiments of wings : example, Gryllus, the 

 Grasshopper. 



