4 POPULAR ENTOMOLOGY. 



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 Mies ; the minor distinctions 

 depend principally on the number of the legs and prolegs, 

 but for these the student must refer to larger works. Hav- 

 ing attained its full size after several times changing the skin, 

 the larva undergoes its final and most important transfor- 

 mation, 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 ad- 

 mirable 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 heads those whose transformation is 

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

 them into five kinds, as follows : 



Pupa cow/pleta, 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. 



