276 On Aquatic Carnivorous Coleoptera or Dytiscide, 
pone medium rufo-testaceis ; pedibus rufis, posterioribus magis obscuris; antennis 
testaceis. Long. 33, lat. 2 m.m. 
The yellow colour at the sides of the thorax is here very broad ; the spot at the | 
shoulder of the elytra is also large, and between it and the suture there are obscure 
traces of another basal spot, the spot behind the middle is rather small. 
Persia. 488. 
57. Hydrocanthus morsbachi, Wehncke, Berl. Zeit. 1876, p. 222.—Ovalis, sat 
convexus, posterius attenuatus, pernitidus, niger, capite anterius anguste, prothorace 
ad angulos anteriores, elytris maculis duabus ad basin, aliaque transversa pone 
medium rufo-testaceis ; antennis testaceis, pedibus rufis, posterioribus obscurioribus. 
Long. 3 m.m., lat. 13 m.m. 
The yellow colour on the head and at the anterior angle of the thorax is very 
small in extent, on the other hand the two basal spots on the elytra are rather 
large, and the post-medial spot is broad, so as to form a transverse mark. I have 
seen but one individual. 
Cochin China, (Wehncke). 613 
58. Canthydrus frontalis, n. sp.—Ovalis, sat convexus, posterius attenuatus, 
pernitidus, niger, capite anterius, prothorace ad angulos anteriores, elytris maculis 
duabus magnis ad basin fasciaque pone medium rufo-testaceis; antennis testaceis, 
pedibus rufis, posterioribus obscurioribus. Long. 2%, lat. 13 m.m. 
In this species the limit between the colours on the head is angular: the marks 
on the elytra are a longitudinal oblong one at the shoulder, a rather large spot 
between that and the suture, and a transverse spot or short band beyond the middle. 
Arabia; Bombay. 487. 
59. Canthydrus sexpunctatus, n. sp.—Ovalis, sat convexus, posterius attenuatus, 
pernitidus, niger, capite anterius rufo, prothorace ad angulos anteriores, elytrisque 
maculis sex testaceis, pedibus rufis, posterioribus obscurioribus : antennis testaceis. 
Long. 2%, lat. 1¢ m.m. 
The smaller extent of the yellow colour on the thorax seems to be almost all that 
distinguishes this species from Hydrocanthus luctuosus (No. 60). 
India; Tranquebar. 486. 
§0. Hydrocanthus luctuosus, Aubé, M.C.—Ovalis, sat convexus, posterius attenua- 
tus, pernitidus, niger, capite et prothoracis lateribus rufo-testaceis, illo vertice magis 
