120 



ARTHROPODA 



FIG . 141. Photograph of a damsel fly just out of the pupal skin below. Natural size. 



the wings pressed together over its back and feed it house 

 flies of which it will devour as many as two dozen hi a few 

 minutes. 



Characteristic Features of Insects 



The insects agree in having a segmented body composed 

 of three clearly defined parts, the head, thorax, and abdo- 

 men. The head bears two hairlike processes, the antenna?, 

 a pair of large compound eyes, and several ocelli or simple 

 eyes. The wings varying in number from none to two 

 pairs are attached to the thorax and present nervures or 

 veins. These are air tubes or tracheae. The legs, of which 



