64 



BRANCH ARTHROPODA. 



casting of the skin liberates the adult winged Insect, the 

 imago (i ma'go). In the complete metamorphosis of the 

 fly, moth, and beetle, the young are voracious feeders, 

 storing up sufficient material to enable them to pass the 

 pupa stage in quiescence. 



The several orders may be tabulated as follows : 



Develop7~nent direct, without metamorphosis : No wings. Thf/s a nil'ra. 

 Metamorphosis incomplete : Wings, four ; posterior 



folded under short anterior Der ma t&p' te rd. 



Metamorphosis incomplete : Wings, four ; membranous ; 



reticulate .' PseU do net! r&p'te rd. 



Metamorphosis complete : Wings, four ; membranous ; 



reticulate Neil rbp' te rd, 



Metamorphosis incomplete : Wings, four ; posterior fold- 

 ing like a fan Or thdp' te rd. 



Metamorphosis incomplete : Mouth - parts formed for 



piercing and sucking He imp' te rd. 



Metamorphosis complete : Wings, four ; anterior horny ; 



posterior membranous Colebp'terd. 



Metamorphosis complete: Wings, two; membranous Dip'terd. 



" absent Aph a nip' (era. 



" covered with minute 



scales Lip i dop'te rd. 



Metamorphosis complete : Wings, four ; membranous ; 



sparsely reticulate H$ men &p' te rd. 



FIG. 101. 



Lep"is'ma sac cha 

 ri'na. Spring-tail. 

 (.Enlarged.) 



ORDER, THYSANURA (this a nu'ra). 



The Spring-tails are placed lowest among 

 the Insects. These small animals are found 

 in damp places, among musty books, under 

 carpets, beneath nearly every piece of bark 

 that has laid for some little time on the 

 ground, in pools of snow water, and even in 

 snow itself. The body is covered with small 

 hairs or scales. The long terminal filaments 

 are often capable of being bent under the 

 body, and, when quickly released, spring the 

 animal a considerable distance. Wings are 

 absent, and the development is direct. 



