470 INSECTA. 



cal, and the last or the eighth conical ; these latter joints form an 

 almost cylindrical and greatly elongated club, which terminates in a 

 point. The maxillary palpi are a little shorter than the antennae. 

 The eyes are large and prominent. The thorax is almost semilunar. 

 The elytra completely clasp the abdomen. The pectus is destitute 

 of a sternal spine. The extremity of the four posterior tibiae is fur- 

 nished with a bundle of setse almost as long as the tarsus. The scu- 

 tellum is small, triangular, elongated, and narrow. 



The only species known, G. Leachii, is small, and foreign to 

 Europe, i believe it is from South America. 



All the remaining Hydrophilii have nine joints in their antennae ; 

 the club is oval or ovoid. The body is not susceptible of being con- 

 tracted into a ball. 



In tlie largest species, the two intermediate joints of the antennal 

 club, or the seventh and eighth, are reniform or irregularly lunate, 

 obtuse at one end, prolonged, arcuated, and pointed at the other, 

 with a remarkable space between them ; the first of this club is 

 cupulate and most prolonged anteriorly. The middle of the ster- 

 num is elevated into a carina, and terminated posteriorly in a point 

 more or less long, and very acute. The maxillary palpi are longer 

 than the antennae ; their last joint is shorter than the penultimate. 

 The tarsi, particularly the last, are compressed, fringed with hairs 

 or cilia along their internal side, and terminated by two hooks, gener- 

 ally small, unequal, and unidentated inferiorly. The scutcllum is 

 tolerably large. These species compose the genus 



Hydrophilus, Geoff., Fab., Leach. — Dytiscus, Lin. 



Here the sternal spine is strongly prolonged behind. The last 

 joint of the two anterior tarsi of the males is dilated in the form of 

 a triangular palette. The scutellum is large. They form the Hy- 

 drous of M. Leach *. 



The larvae resemble a sort of soft, conical, and elongated worms, 

 furnished with six feet, and a large squamous head, more convex 

 underneath than above, armed Avith strong and hooked mandibles. 

 They respire by the posterior extremity of the body, are very vora- 

 cious, and do great injury to fish ponds by devouring the spawn. 



H.piceus, Fab.; Oliv., Col. Ill, 39, Ij 2. 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 

 striae on the elytra, the posterior extremity 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 anus of the female is provided Avith two fusi, by means 

 of which she constructs an ovoid cocoon, surmounted with a 

 point, resembling an arcuated brown horn. Its external tissue 

 is a gummy paste, which, though fluid at first, subsequently 



* Zool. Miscel., Ill, p. 94. 



