AQUATIC HEMIPTERA. 



These are sometimes classed as a subfamily of Pentatomi- 

 da^. Some species are large and brightly colored but they 

 are not usually common. 



CORIXID.E 



The Water-boatmen (most boatmen are that kind) 

 swim "right side up." Compare Notonectidae. They 

 are slightly heavier than water and rest on the bottom or 

 on aquatic plants, but when they come up for air, the 

 surface tension is sufficient to hold them at the top without 

 much effort on their part. At such times, they float in a 

 horizontal position, taking air directly into the thoracic 

 spiracles and renewing the supply of air which is carried 

 by hairs when they dive. It is said that these insects, 

 while submerged, but especially at night, make a tolerably 

 loud and sustained noise by rubbing their beak with their 

 front legs. The eggs are usually fastened on, not in, 

 submerged objects; the eggs of certain specie in the lakes 

 near the City of Mexico are so abundant that they are 

 gathered by the Mexicans and used for food. This family 

 is predaceous and its members, like their relatives, are 

 attracted, in their nocturnal flights, by light. The princi- 

 pal genus in our region is Arctocorixa Corixa of most 

 publications (Plate XXV). 



BELOSTOMID^E 



This family contains the Giant Water-bugs; also called 

 Electric-light Bugs because the adults are frequently 

 noticed flying about electric lights. Some of the tropical 

 species are the largest of Hemiptera, being four and five 

 inches long. The broad, flat hind legs and the flat body, 

 with a keel in the middle underneath, well fit them for 

 aquatic locomotion. The sharp-hooked front legs and 

 the short, powerful beak make their predatory habits not 

 to be depised by even fair-sized fish. They lurk on muddy 

 bottoms, often slightly covering themselves with mud or 

 leaves, ready to dart out after the unwary. Before men- 

 tioning one of the interesting habits of some of them we 

 must, unfortunately, note a change in names: the generic 

 name, Belostoma, which has been used in most publications, 

 should be Lethocerus, and Zaitha becomes Belostoma. 



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