THE HEMIPTERA 



185 



swimmers. Like the latter group they often leave the water and fly at 

 night and are frequently attracted to lights. 



Family Nepidae. — The water-scorpions as these insects are called, 

 live in fresh-water ponds and pools. Two types of form are included, 



Fig. 175 Fig. 176. 



Fig. 175. — Water-scorpion {Ranalra americana Montd.) about natural size. {Original.) 

 Fig. 176. — Giant Water- bug (Lethocerus americanus Leidy), natural size. {Original.) 



one having a long, slender body and long legs (Fig. 175), the front pair of 



which, unusually long, are constructed for grasping their prey which 



consists of small insects. In the other type the body is short, rather broad, 



and flat. In both a long tube consisting of two pieces which can be pressed 



together to form the tube, joins the hinder end of the 



body and while the insect is an inch under water in , 



some cases, this tube is pointed upward until its tip 



is out of water and through it the insect obtains air. 



The slender forms lying quiet on the bottom of pools 



resemble dead twigs and thus obtain the concealment 



needed to enable them to get within reach of their 



food. 



Family Belostomidae. — These insects are gen- 

 erally termed the giant water-bugs. Some of them 

 are the largest members of the Hemiptera, being 

 two, three or more inches long, broad, flat and brown 

 in color (Fig. 176). They live in fresh water and 

 feed on insects and even small fish and are thus 

 sometimes injurious in the production of food fishes. They fly by 

 night and are frequently attracted to electric lights, which has led to 

 the larger species being sometimes called "electric-light bugs." In some 

 of the smaller species (Fig. 177) the eggs are laid on the back of the male 

 who is thus obliged to carry them around until they hatch. 



Fig. 177. — Male 

 Belostomid {Belostoma 

 flumineum Say) carry- 

 ing eggs on its back. 

 Natural size. {Orig- 

 inal.) 



