428 CLASS INSECTA. 



antennae appear to me to be composed of but eight articula- 

 tions, the fifth of which is dilated in the manner of a spine 

 at the internal side, the following in an inverted cone, elon- 

 gated, the seventh cylindrical, and the last or eight, conical. 

 These last articulations form a very elongated knob, almost 

 cylindrical, and terminating in a point. The maxillary 

 palpi are a little shorter than the antennae. The eyes are 

 bulky and projecting. The corslet is almost semi -lunar. 

 The elytra embrace the abdomen entirely. The breast is 

 without a sternal spine. The four posterior legs, have at 

 their extremity a bundle of silky hairs, almost as long as 

 the tarsus. The scutellum is small, and in an elongated and 

 narrow triangle. 



The only known species (G. Leachii) is small and exotic. 

 I believe it comes from South America. 



All the other hydrophillii have nine articulations to the 

 antennae, and the knob is ovaliform or ovoid. The body 

 is not susceptible of being contracted into a ball. 



The largest species have the two intermediate articulations 

 of the antennary knob, or the seventh and eighth, in the 

 form of a kidney, or irregular crescent, obtuse at one of 

 their ends, elongated, arched, and pointed at the other, with 

 a vacancy or remarkable separation between them ; the first 

 of this knob is cupular, more elongated on the anterior side. 

 The middle of the sternum is raised into a keel, and ter- 

 minates posteriorly in a point, more or less long and very 

 sharp. The maxillary palpi are longer than the antennae, 

 Avith the last articulation shorter than the preceding The 

 tarsi, especially the last, are compressed, garnished with a 

 fringe of hairs on the internal side, and terminated by two 

 generally small crooks, unequal and unindented below. The 

 scutellum is tolerably large. 



These species will compose the genus. 



