COLEOPTERA. 411 



We might separate from them some species * in which the body 

 is almost globular, and where the last joint of the four anterior tarsi 

 is very small and projects but little beyond the preceding one 

 Hyphydrus, Lat. The body of the rest is oval, and not so thick f. 



Sometimes the antennae are slightly dilated and wider in the middle 

 of their length ; the last joint of the labial palpi is emarginate, and 

 appears forked. 



NOTEBUS, Clairv. 



No scutel ; tarsi consisting of five distinct joints, and the two first 

 of the four anterior dilated in the males, forming an elongated 

 palette ; first joint of the two anterior tarsi covered by a broad lamini- 

 form spur, the part of the pectus bearing the last legs with a deep 

 groove on each side J. 



The others have but ten distinct joints in their antennae; their 

 exterior palpi are fusiform, or have a more slender termination taper- 

 ing to a point, and the base of the posterior legs is covered with a 

 large shield. 



The body is convex and ovoid underneath, as in Hygrobia ; but 

 there is no scutel, and all the tarsi are filiform, composed of five 

 almost cylindrical joints, and have nearly the same form in both 

 sexes. They are the 



HALIPLUS, Lat. HOPLITUS, Clair. CNEMIDOTUS, Illig. 

 The second genus of the Hydrocanthari, or the 



GYRINUS, Lin. 



Comprises those in which the antennae are clavate and shorter 

 than the head ; the two first legs are long and project like arms ; the 

 remaining four are compressed, wide, and pinnate. There are four 

 eyes. 



The body is oval and usually very glossy. The second joint of 

 the antennae, which are inserted in a cavity before the eyes, is pro- 

 longed exteriorly in the form of an auricle, and the following 

 joints || are very short, crowded, and united in one almost fusiform 

 and slightly curved mass. The head is sunk in the thorax almost 

 to the eyes, which are large, and divided by a border, in such a way 

 that two are above and two underneath, The labrum is rounded 

 and strongly ciliated before. The palpi are very small, and the 



The Hyd. gibba, waits, tcripta, Fab. ; Hyphydnts lyraivs, Schcenh., Synon. Insect., 

 II, iv, 1. 



f The Dytisci in<eqvalit, reticvlatus, confluent, picipti, ptV/v, geminus, lineafvs, ha- 

 Irtui*, duodccim-pustulatvi, donalit, tex-pvstvlatus, puluslris, depress**, liluratvs, planvs, 

 erythrocejjhalus, nigrita, yranularia, Fab. See Schocnherr, Synon. Insect. II, genus 

 Uyphydnu: Pan*., Index Entom., genus Hydropona , and Clairv., Entom. Helv. 

 II. the same genus. 



J Dytisnu crassicornis, Fab. ; Clairv., Entom. Helv., II, xxxii. 



Tbe Dytiad/ttim*, impress** and obliqvus, Fab. See Latr., Gener. Crust, et 

 Insect., I, p. 234 ; Clairv., Entom. Helv., II, genus Hophtus, XXXI ; Panz., Ind. 

 Entom., genus id., and Schcenherr, Synonym. Insect. II, genus Cnemidotvs. 



|| But seven are distinctly visible, the first and last of which are the longest. 



