On Aquatic Carnivorous Coleoptera or Dytiscide. 333 
Closely allied to H. nigricans, but broader and with the upper surface nearly 
opaque ; but readily distinguished by its shorter, broader antenne. 
I have seen only a single male, whose front and middle tarsi are distinctly 
dilated. 
Madagascar. 150. 
214. Hydrovatus badeni, (Wehncke), n. sp.—Nigro-piceus, latus, convexus, dense 
fortiter punctatus, antennis pedibusque rufis. Long. 44, lat. 3§ m.m. 
Mas, nitidus, antennis sat elongatis et gracilibus, tarsis anterioribus et inter- 
mediis dilatatis. 
Fem., opaca, magis obsolete punctata, antennis paulo brevioribus, tarsis latius- 
culis, sed articulis basalibus haud dilatatis. 
Allied to Hydrovatus nigricans, (No. 212), but a good deal larger and with great 
differences between the two sexes. 
Madagascar. 1051. 
915. Hydrovatus compactus, n. sp.—Convexus, ferrugineus, nitidus, lateribus 
valde rotundatis, crebre sat fortiter punctatus ; trochanteribus posterioribus valde 
distantibus. Long. 32, lat. 2 m.m. 
Antenne rather long and slender; clypeus with a distinct and uninterrupted 
margin. Thorax closely and distinctly punctured. Elytra rather closely and 
coarsely punctured. Coxe externally rather closely punctured. The general 
form is very convex and compact, and greatly rounded at the sides, so as to be much 
narrowed in front and behind. 
This species is closely allied to Hydrovatus nigricans, (No. 212), but is paler in 
colour and much smaller, it is even more convex and the elytra are less elongate. 
The individual described is a male but the tarsi are only about half as broad as in 
the ¢ of H. nigricans. In my collection there is a specimen which, from its resem- 
blance in form, I believe to be the female of this species, but it differs remarkably 
from the ¢ by its sculpture, the whole of the upper surface being quite dull, densely 
reticulate, and with the sculpture obsolete, and the punctuation of the coxe is finer 
and more sparing. 
Africa, (Gaboon). 20. 
216. Hydrovatus nigrita (Wehncke), n. sp.—Nigro-piceus, nitidus, convexus, latus, 
dense fortiter punctatus, antennis pedibusque rufis; trochanteribus posterioribus 
bene distantibus. Long. fere 4, lat. 25 m.m. 
Extremely like Hydrovatus nigricans, (No. 212), but rather smaller and distinctly 
narrower, the antenne slightly shorter, the hind and middle legs not quite so widely 
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