386 INSECTA. 



FAMILY V. 



PALPICORNES.(l) 



In our fifth family of pentamerous Coleoptera, as in the fourth, 

 we observe antennae terminating in a club, usually perfoliaceous, but 

 consisting of nine points at most in all, and inserted under the late- 

 ral and projecting edges of the head; they are never much longer 

 than the latter and the maxillary palpi, and frequently even shorter 

 than the last mentioned organs. The mentum is large and scuti- 

 forra. 



The body is usually ovoid or hemispherical, convex or arched. 

 The legs in several are adapted for natation, and then consist of but 

 four very distinct joints, or of five, the first of which is much shorter 

 than the second; all the joints are entire. 



Those in which the legs are natatory, the first joint of the tarsi 

 is much shorter than the following ones, and the maxilte are en- 

 tirely corneous, will form our first tribe, that of the Hydrophilh, 

 which embraces the genus 



Hydrophiius, Geofi". 



Linnaeus merely made these Insects a division (the first) of his genus Dytis- 

 cus, but their anatomy is essentially different. In the true Hydrophiius the 

 sternal spine is strongly prolonged behind. The last joint of the two an- 

 terior tarsi of the males is dilated in the form of a triangular palette. The 

 scutellum is large. 



The larvx resemble a sort of soft, conical, and elongated worm, furnish- 

 ed with six feet, and a large squamous head, more convex underneath than 

 above, armed with strong and hooked mandibles. They respire by the 

 posterior extremity of the body, are very voracious, and do great injury to 

 fish ponds by devouring the spawn. 



H. piceus. Fab. An inch and a half long; oval; of a blackish-brown, 

 polished, or as if covered with a varnish; antennal club partly reddish; some 

 slightly marked strix on the elytra, the posterior exti'emity of which is 

 rounded laterally, and prolonged into a small tooth at the internal angle. 



It swims and flies well, but walks badly. When held loosely in the hand, 

 its sternal spine sometimes inflicts a wound. 



The extremity of the female is provided with two fusi, by means of 

 which she constructs an ovoid cocoon, sui-mounted with a point, resembling 



(1) Palpi-horned. 



