On Aquatic Carnivorous Coleoptera or Dytiscida. 331 
Antenne rather short, and stout. Clypeus extremely obsoletely margined. 
Thoracic punctuation very slight. Elytra rather sparingly but distinctly and evenly 
punctured, Coxe sparingly punctured. 
This species is intermediate in form between Hydrovatus and a small Hydroporus, 
but in its structure it departs but little from Hydrovatus clypealis (No. 179). 
Australia, (Rockhampton). 18. 
208. Hydrovatus pumilus, n. sp.—Oblongus, minus convexus et elongatus, sat 
nitidus, testaceus, sparsim subtiliter punctatus, ad apicem breviter acutus; coxis 
posterioribus sparsim obsolete punctatis. Long. 14, lat. 1 m.m. 
Though very closely allied to H. parallelus, this is a little smaller and decidedly 
shorter. It is the smallest species of the genus and the one in which the articula- 
tions of the hind legs are least separate. 
Sumatra, (two individuals sent by Wehncke). A specimen from “India” sent also from Wehncke differs 
in being a little less shining. 401. 
209. Hydrovatus opacus, n. sp.—Latus, brevis, ferrugineus, evidenter reticulatus, 
subopacus, crebre fortiter punctatus; antennis sat elongatis; processu prosternali 
antice obtuso et apice leviter deflexo. Long. 2, lat. 1: m.m. 
Mas, antennis crassiusculis, medio leviter incrassatis. 
Fem., antennis sat tenuibus simplicibus. 
Longer but not at all broader than H. cuspidatus, (No. 180), and with closer and 
more regular, and rather coarser punctuation, and with the front tibize rather longer 
and more slender; in the female the antenne are rather longer than they are in 
H. cuspidatus; and in the male they are a good deal longer than in the female, 
and the middle joints (especially 4-6), are rather thicker than the others, the tarsi 
in this sex are also a good deal more dilated than in the other: the form of the 
point of the prosternal process distinguishes the species from H. confertus (No. 202), 
and its allies, which it greatly resembles. 
Australia, (Rockhampton). 12. 
210. Hydrovatus obtusus, Motsch., M.C.—Testaceo-ferrugineus, minus latus, 
ad apicem minus acuminatus, crebre evidenter reticulatus, subtiliter sat crebre 
punctatus. Long. 23 m.m., lat. 1: m.m. 
Smaller and a good deal narrower than H. cuspidatus, (No. 180), and much less 
acuminate behind, and with the punctuation rather finer and more evenly distributed. 
The large punctures on the coxe are rather sparing and subobsolete, being but 
little impressed. 
The only specimen I have seen of this species is in the collection of the Brussels 
TRANS. ROY. DUB. SOC., N.S., VOL, II. 2x 
