435 On Aquatic Carnivorous Coleoptera or Dytiscide. 
Hind coxal cavities not quite approximate, wing cases variegate. 
Group l. ; 
(North American species), Nos. 495 to 500. 
Group 2. 
§ nti coxal cavities quite approximate, thoracic side margin 
generally thickened, tarsi with third joint much lobed, and 
under surface red: (North American species), Nos. 501 to 521. 
thickened, under surface nearly or quite black, prosternal 
process short or moderately long. Nos, 552 to 629. 
cesses, not in the least abbre- 
viated at apex behind, wide 
Plate vii., fig. 48. 
Group 4. 
Hind coxal cavities quite approx., thoracic side margin not 
Group 5. 
Hind coxal cavities quite approximate, prosternal process elongate. 
No. 630. 
( Group 6. 
Hind coxal cavities minutely separated, surface unicolorous, pros 
| ternal process small. Nos. 631 to 636. 
{ Group 7. 
Hind coxal cavities distinctly separated, surface unicolorous, pros- 
| ternal process large. Nos. 637 to 639. 
f Group 8. 
Hind coxal cavities very distinctly separated, prosternal process 
small. Nos. 640 to 644. 
| 
| 
Mesial line between coxal | 
| 
l 
Group 3. 
Mesial line between coxal pro- + wing cases variegate. Nos. 522 to 551. 
cesses more or less abbreviated 
at hind extremity, vide Platevi., Group 9. 
fig. 49. | Wig cases not variegate, coxal lobes highly developed. Nos. 
645 to 649. 
California.—Hydroporus lateralis, Boh. (No. 1392), gen. dub. ; Caffraria.—Hydroporus longulus, Muls. 
(No. 1394), near No. 632; France.—Hydroporus lucasi, Reiche (No. 1395), near No. 569 ; Algeria.— 
Hydroporus melancholicus, Motsch. (No. 1398); Kamtschatka.—Hydroporus monilicornis, Sahl. (No. 
1400), near No. 562; Lapland.—Hydroporus multiguttatus, Regt. (No. 1401), near 569; Syria.— 
Hydroporus mutatus, Har. (No. 1402), gen. dub.; Natal.—Hydroporus niger, Say (No. 1404); North 
America.—Hydroporus notabilis, Lec. (No. 1405), near No. 628; North America.—Hydroporus nudatus, 
Say (No. 1406), ? near 525; Mexico.—Hydroporus obtusipennis, Sahl. (No. 1408); Lapland.— 
Hydroporus opacus Wehncke (No. 1409), ? No. 598 var.; Lapland.—Hydroporus oppositus, Say 
(No. 1410), near No. 513 ; North America.—Hydroporus persimilis, Crotch (No. 1413), near No. 638 ; 
North America.—Hydroporus piceus, Steph. (No. 1414); England.—Hydroporus planatus, Mann. 
(No. 1416) ; North America.—Hydroporus politus, Macl. (No. 1417) gen. dub. ; Australia. —Hydroporus 
productus, Fairm. (No. 1419) ; Algeria.—Hydroporus puberulus, Lec. (No. 1421),? = No. 1348; North 
America.—Hydroporus pulcher, Motsch. (No. 1423)? near 522; North America.—Hydroporus roffi, 
Clk. (No. 1424), near No. 527; Mexico.—Hydroporus rufinasus, Mann. (No. 1425), near No. 602 ; 
North America,—Hydroporus sabaudus, Fauv. (No. 1426), near No. 612; Europe.—Hydroporus 
sedilloti, Regt. (No. 1428), near No. 544; Syria.—Hydroporus sericatus, Say (No. 1432), near No. 508 ; 
Mexico.—Hydroporus subalpinus, Th. (No. 1434), near No. 561; Sweden.—Hydroporus submuticus, 
Th. (No. 1435), near No. 601 ; Sweden.—Hydroporus subtonsus, Lec. (No. 1487), near No. 602; North 
America.—Hydroporus thoreyi, Clk. (No. 1442), gen. dub. ; Australia.—Hydroporus derelictus, Clk. 
(No. 1443)? No. 612 var. ; Scotland.—Hydroporus truncatus, Mann. (No. 1444); North America.— 
Hydroporus undecimmaculatus, Clk. (No. 1446), gen. dub.; Australia.—Hydroporus viticollis, Boh. 
No, 1449), gen. dub. ; Caffraria. 
