BRANCH ARTHROPODA; CLASS INSECT A : THE INSECTS 199 



62 and 63), the worst insect pests of oranges, the squash- 

 bugs and cabbage-bug and a host of others. Some of 

 the Hemiptera, for example, the lice and bed-bugs, are 

 predaceous, sucking the blood of other animals. 



The water-striders (fig. 64) catch other insects, both 

 those that live in the water 

 and those which fall on to 

 its surface, and holding the 

 prey with their seizing 

 fore legs they pierce its 

 body with their sharp 

 beak and suck its blood. 

 They lay their eggs in the 

 spring glued fast to water- 

 plants. The young water- 

 striders are shorter and 

 stouter in shape than the 

 adults. 



The Water-boatmen FIG. 64. A water-strider, Hygrotrechns 

 (fig. 6 5 ) and back-swim- SP " (F-m Jenkins and Kellogg., 

 mers swim and dive about in the water, coming more 

 or less frequently to the surface to get a supply of air. 



This air they hold under the 

 wings, or on the sides and 

 under part of the body en- 

 tangled in the fine hairs on 

 the surface. The insects 

 appear to have silvery spots 

 on the body, due to the 

 presence of this air. The 



FIG. 65. A water-boatman, Corisa* "rowing " legs of the water- 

 sp. (From Jenkins and Kellogg., boatmen (Corisd] are the 



hindmost pair; in the back-swimmers (Notonecta) they 

 are the middle legs. 



The cicadas (fig. 66) are the familiar insects of summer 



