250 CLASS INSECTA. 



lation of the two anterior tarsi is covered in the same indivi- 

 duals by a broad spur, plate-formed. The pectoral piece 

 which bears the hinder feet, has on each side a deep groove. 

 Dytiscus crassicornis. Fab. Clairv. Entom. Helv. II. xxxii. 



The others have but six distinct articulations on the an- 

 tennae. Their external palpi terminate oval-like, or by a 

 more slender articulation, and going into a point. The base 

 of their posterior feet is covered with a large lamina, of a 

 buckler-form. 



The body is gibbous underneath, and ovoid, as in hygro- 

 bia. But they have no scutellum, and all their tarsi are 

 filiform, with five distinct articulations, and almost cylindri- 

 cal, and have pretty nearly the same form in both sexes. 

 These are 



Haliplus, Lat. Hoplitus, Clairv. Cnemidofus, Ilig.* 

 The second genus, or that of 



Gyrinus, 



Comprehends those whose antennae are club-formed, and 

 shorter than the head. The first two feet are long, advanced 

 in the form of arms, and the other four very much com- 

 pressed, broad, and fin-formed. The eyes are four in num- 

 ber. 



The body is oval, and usually very shining. The antennae, 

 inserted in a cavity in front of the eyes, have the second arti- 

 culation prolonged externally in the form of an auricle, and 

 the following articulations (of which but seven are visible, 

 the first and last of which are the longer), very short, very 



* The Dytisci : fulvus, impressus, obliquus, of Fabricius. See Latreille, 

 Gener. Crust, et Insect. I. p. 234; Clairv. Entom. Helv. torn. II. genus 

 Hoplitus, XXXI. Panz. Ind. Entom. genus id., and Schoenherr. Synora. 

 Insect. II. genus Cnemidotics. 



