On Aquatic Curnivorous Coleoptera or DytiscidcB. 493 



I. 46.— Genus AGABUS. 



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 bunded 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 ; 

 J 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 coxee, 

 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. Agabiis amrenns, Solsky, (No. 1179 

 huj. op.) Turkistan. — Agabns atratus, Mann. (No. 1180); Russian America. — Agabiis confertus, Lee. 

 (No. 1182) ; North America. — Agabus foveolatus, Muls. (No. 1185), very closely allied to No. 706; 

 France.- — Agabus fnsco-senescens, Regt. (No. 1186) ? near No. 737; Austria. ^Agabus glacialis, Hoch. 

 (No. 1187), near No. 671; Caucasus. — Agabus goryi, Aube (No. 1188), near No. 670; Smyrna. — 

 Agabus gougeleti, Eeiche, (No. 1189)? No. 714 var. ; Corsica. —Agabus hoeffneri, Aub6 (No. 1190), near 

 No. 720 ; Sweden. — Agabus irregularis, Maun. (No. 1193) ?=No. 688; North America. — Agabus kess- 

 lei-i, Hoch. (No. 1194)1 near No. 757? Russia. — Agabus luniger, Kol. (No. 1196; ! No. 713 var. j 

 Armenia. — Agabus morosus, Lee. (No. 1197)? near No. 707 ; North America. — Agabus opacus, Aube, (No. 

 1199); Finland. — Agabus rotiindatus, VVehncke (No. 1 200) ? near No. 694 ? Sardinia.- Agabus scapularis ; 

 Mann. (No. 1201) i=No. 710; North America. — Agabus subopacus, Mann. (No. 1202); North 

 America. — Agabus terminalis, Melsh. (No. 1204); North America. — Agabus venturii, de Bertolini 

 (No. 1206) Italy. — Anisomera recta, Lee. (No. 1208), near No. 662; North America. — Colymbetes 

 alpinus, Mutsch. (No. 1210) ?=No. 736? Mongolia.— Colymbetes basalis, Geb. (No. 1214) ; Siberia.— 

 Colymbetes co.stulatus, Motsch. (No. 1218) ; Siberia.— Colymbetes dilatatus, Brulle (No. 1220) ? No. 670 

 var.? Europe. —Colymbetes discolor, Harr. (1222); North America. — -Colymbetes fossigei-, Motsch. (No. 

 1227); North America. — Colymbetes phseoptenis, 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, Lee. (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. — 

 Gaurodjiies ovalis, Sahl. (No. 1303); Gothland. — Gaurodytes suturalis, Crotch. (No. 1304); North 

 America. 



The systematic position of the following is more doublful, but may possibly be with Agabus : — Agabus 

 dilatatus, Sol. (No. 1183); Chili. — Agabus eminens, Kirsch. (No. 1184); Peru. — Anisomera bistriata, 



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