On Aquatic Carnivorous Coleoptera or Dytiscide. 339 
226. Hyphydrus obniger, Chev., M.C.—Ovalis, nitidus, convexus, sat angustus 
et elongatus, piceus, capite thoraceque dilutioribus, antennis pedibusque rufis ; 
prothorace crebre, irregulariter, subtiliter punctato ; elytris sat sparsim et subtiliter 
punctatis. Long. 42 m.m., lat. 22 m.m. 
This species 1s narrower than P. punctatus, and readily distinguished by the 
much finer punctuation of the elytra; this towards the sides is a good deal closer 
and coarser than it is on their sutural portion. The species is very closely allied 
to P. obesus, but is more elongate, the punctuation of the thorax is coarser, while 
that of the elytra is rather finer (especially on the sutural portion), and less close 
and distinct. 
Cuba. 50. 
227, Pachydrus obesus, n. sp.—Ovalis, nitidus, convexus, sat latus, piceus, capite 
thoraceque dilutioribus, antennis pedibusque rufis; prothorace irregulariter, sub- 
tiliter, sparsim punctato; elytris crebre vix fortiter punctatis. Long. 4, lat. 
22 m.m. 
The surface of the thorax in this species is but little uneven, but the punctures 
are scattered in an irregular manner, and are quite fine, being not at all coarser than 
those of the head. The punctures of the elytra are rather small, but rather deep and 
distinct. The species is shghtly narrower in its form than P. punctatus, but is 
very readily distinguished therefrom by its punctuation. 
Venezuela, (Cumana). 91. 
228. Pachydrus brevis, n. sp.—Ovalis, sat nitidus, latus, piceus, capite thoraceque 
dilutioribus, antennis pedibusque rufis ; prothorace superficie vix inzequali, sparsim 
punctato ; elytris crebre sat fortiter punctatis. Long. 4, lat. 23 m.m. 
This species is intermediate in form and sculpture between Pachydrus cribratus and 
Hyphydrus obniger, (No. 226). Itis rather more elongate than Pachydrus cribratus, 
and is readily distinguished by the much less dense sculpture of the elytra; it is a 
good deal less elongate than Hyphydrus obniger, and has the sculpture of the 
upper surface much coarser, deeper and closer ; it differs from Pachydrus cribratus 
very shehtly, except in the sculpture, the distinction in this respect being however 
very conspicuous. 
Porto Rico. Antigua. 158. 
TRANS, ROY. DUB. SOC., N.S., VOL. I. 2¥ 
