65 



G en us XXIV. D YTISC US. 



GENERIC CHARACTER,. 



Antemw setaceous. Palpi six, filiform. Man- 

 dibula thick, arched, terminating in two 

 or three teeth. Hind feet hairy, made for 

 swimming. 



General Observations. 



This is an amphibious genus, inhabiting the 

 water in the day-time, but in the evening crawl- 

 ing to land and taking flight. They swim with 

 great agility, and nothing can be better calcu- 

 lated than their hind legs for the purpose. They 

 are two feathered oars, of due proportions, pre- 

 senting a resistance to the stream, which by a 

 muscular effort of the insect impels the body 

 forward with great celerity. Although capable 

 of living a long while under water, the Dytis- 

 cus is occasionally obliged to come to the sur- 

 face for air. And here we cannot but notice 

 one of those simple, but effective, contrivances, 

 by which the insect accomplishes its end with- 

 out being conscious of the means. The body 



G 3 



