On Aquatic Carnivorous Coleoptera or Dytiscide. 493 
I. 46.—Genus AGA BUS. 
Side of prothorax with a raised margin ; labial palpi with terminal joint not 
incrassate ; wings of metasternum variable in size, but never so very short as to 
be parallel-sided ; coxal lines distinctly sinuate ; hind tarsi on their outer side with 
the posterior margins of the joints nearly straight, not lobed. 
This genus consists of nearly a hunded species found in the northern parts of the 
Old and New Worlds ; it is one of much interest, but of extreme difficulty so far as 
regards the determination of the species, on account of the great similarity in 
general appearance, and the considerable variation in structural characters from 
species to species. I have arranged the species in twenty-three groups, some of 
them natural, some clearly artificial; to tabulate these groups in an analytical 
manner would only confuse the student and lead him into errors of determination ; 
{ have therefore contented myself with placing at the head of each group the 
characters that have induced me to adopt it. These characters are drawn largely from 
the coxal lines and processes, and the form of the anterior border of the hind coxe, 
the metasternal wings, the approximation of the middle legs, and development of 
the metasternal groove, and the prosternal process.” 
* The following species also probably belong to the genus Agabus. Agabus ameenus, Solsky, (No. 1179 
huj. op.) Turkistan.— Agabus atratus, Mann. (No. 1180); Russian America. 
(No. 1182); North America.—Agabus foveolatus, Muls. (No. 1185), very closely allied to No. 706; 
France.—Agabus fusco-znescens, Regt. (No. 1186)? near No. 737 ; Austria.—Agabus glacialis, Hoch. 
(No. 1187), near No. 671; Caucasus-Agabus goryi, Aubé (No. 1188), near No. 670; Smyrna.— 
Agabus gougeleti, Reiche, (No. 1189)? No. 714 var. ; Corsica. —Agabus hoeffneri, Aubé (No. 1190), near 
No. 720 ; Sweden.—Agabus irregularis, Mann. (No. 1193)?=No. 688 ; North America.—Agabus kess- 
leri, Hoch. (No. 1194)? near No. 757% Russia.—Agabus luniger, Kol. (No. 1196)? No. 713 var. ; 
Armenia.—Agabus morosus, Lec. (No. 1197) tnear No. 707 ; North America.—A gabus opacus, Aubé, (No. 
1199) ; Finland.—A gabus rotundatus, Wehncke (No. 1200) ? near No. 694? Sardinia. Agabus scapularis ; 
Mann. (No. 1201)?=No. 710; North America.—Agabus subopacus, Mann. (No. 1202); North 
America.—Agabus terminalis, Melsh. (No. 1204); North America.—Agabus venturii, de Bertolini 
(No. 1206) Ttaly.—Anisomera recta, Lec. (No. 1208), near No. 662; North America.—Colymbetes 
alpinus, Motsch. (No. 1210) !=No. 736% Mongolia.—Colymbetes basalis, Geb. (No. 1214) ; Siberia.— 
Colymbetes costulatus, Motsch. (No. 1218) ; Siberia.—Colymbetes dilatatus, Brullé (No, 1220)? No. 670 
var. ? Europe. —Colymbetes discolor, Harr. (1222); North America.—Colymbetes fossiger, Motsch. (No. 
1227); North America.—Colymbetes pheopterus, Kirb. (No. 1243) ?=No. 1222; North America.— 
Colymbetes ruficeps, Men. (No. 1246); Caucasus,—Colymbetes sobrinus, Motsch. (No. 1249); North 
America. —Colymbetes subquadratus, Motsch. (No. 1253); Siberia—Gaurodytes angusticollis, Sahl, 
(No. 1297) ; Lapland.—Gaurodytes leptapsis, Lec. (No. 1298) ; North America.—Gaurodytes longulus 
(No. 1299) ; North America.—Gaurodytes lutosus, Crotch. (No. 1300) ; North America.—Gaurodytes 
obovatus, Sahl. (No. 1301); Lapland.—Gaurodytes obscuripennis, Sahl. (No. 1302); Lapland.— 
Gaurodytes ovalis, Sahl. (No. 1303); Gothland.—Gaurodytes suturalis, Crotch. (No. 1304); North 
America. 
The systematic position of the following is more doubtful, but may possibly be with Agabus :—Agabus 
dilatatus, Sol. (No. 1183) ; ChilimAgabus eminens, Kirsch. (No. 1184); Peru.—Anisomera bistriata, 
3S 2 
Agabus confertus, Lec. 
