230 On Aquatic Carnivorous Coleoptera or Dytiscida, 
Closely allied to Hydrocanthus australasize, but not so elongate, and of a different 
colour. 
Siam, (Bangkok); (Cochin China fide Wehncke). 477. 
73. Hydrocanthus oblongus, n. sp.—Oblongo-ovalis, sat convexus, pernitidus, 
castaneo-ferrugineus, elytris subiridescentibus, fere impunctatis. Long. 4, lat. 2m.m. 
fn the male the prosternal process is deeply hollowed out, and is nearly im- 
punctate ; and the apical ventral segment has an oblong dull patch in the middle at 
the apex; in the female the prosternal process is flat and is punctured in a variable 
manner; and the apical ventral segment is quite smooth and shining. 
North America. 492, 
74, Hydrocanthus iricolor, Say. M.C.—Ovalis, sat latus, pernitidus, castaneo- 
ferrugineus, elytris subiridescentibus, seriebus tribus fere irregularibus et subdis- 
tinctis punctorum ; antennis minus brevibus. Long. 4s, lat. 22 m.m. 
Larger than Hydrocanthus oblongus, especially broader, and with the antennz 
more developed, and the elytral series of punctures not altogether effaced, 
North America, (Massachusetts). 493. 
75. Hydrocanthus texanus, n. sp.—Ovalis, convexus, pernitidus, ferrugineus, 
elytris nigro-iridescentibus ; corpore subtus posterius plus minusve nigricante. 
Long. 44, lat. 24 m.m. : 
This species is comparatively more convex than Hydrocanthus oblongus, and 
HL. iricolor, and has the elytra blackish ; in respect of the antennz and elytral 
punctuation, and of the size it is intermediate between the two, 
North America, (Texas). 494. 
76. Noterus levigatus, Brullé. Hydrocanthus levigatus, M.C.—Ovalis, pernitidus 
castaneo-ferrugineus, elytris paulo obscurioribus indistincte pallido-reticulatis, 
seriebus punctorum subtilissimis. Long. 5, lat. 22 m.m. 
This species is extremely similar to Hydrocanthus iricolor, but the elytra instead 
of being concolorous are variegated by irregular pale marks forming a sort of coarse 
reticulation, this character is not however very conspicuous till the elytra are opened. 
so as to show the light through them. 
South America; Bahia, Orinoco. 495. 
77. Hydrocanthus atripennis, Say. M.C.—Ovalis, sat latus, valde convexus, 
