OF THE ORDER COLEOPTERA. 281 



frequent the sandy banks of waters, where they run remark- 

 ably fast ; but they differ from them by the manner in which 

 their palpi are terminated. This genus is very numerous, 

 and almost all the species described to the present day are 

 European. Fabricius and Olivier have ranged them among 

 the elaphri and carabi. 



We now arrive at the aquatic coleoptera in which the 

 genus Dytiscus stands foremost. Linnaeus formed two sec- 

 tions of this genus, according to the clavate, and perfoliated 

 or setaceous form of the antennas. Geoffroy, imder the 

 name of hydrophilus, separated those in which these organs 

 exhibit the first of these characters. The other species, or 

 those in which the antennae are setaceous, have preserved for 

 a long time the general name of Dytiscus, but this division 

 is now much more restrained than it was originally. 



The dytisci seem to be amphibious insects. Though the 

 water appears to be their principal element, and although 

 they live there almost continually, they have also the faculty 

 of living on the land and flying in the air. The size of these 

 insects varies very considerably ; some are more than an inch 

 and a half in length, while others are scarcely larger than 

 fleas, and some are found of all the mean sizes between those 

 two extremes. The dytisci are carnivorous, and exceedingly 

 voracious. They live only on other aquatic and terrestrial 

 insects which they catch, and to Avhich they give chase conti- 

 nually. They seize them with their anterior feet, as with 

 hands, and then lift them to their mouth to devour them. 

 Although they can live a long time under water, they have 

 need, however, to respire the air, and they usually do this 

 from time to time. They bring themselves to the surface, 

 and to do so they have only occasion to keep their feet in a 

 state of repose, and to suff'er themselves to float ; being lighter 

 than the water they swim above it at once. It is their hinder 

 part which is then always applied to the surface, and even 



