On Aquatic Carnivorous Coleoptera or Dytiscide. 401 
pallidis plus minusve infuscatis, sat fortiter fere dense sub-ineequaliter punctatis ; 
coxis posterioribus punctis densis profundis ; abdominis lateribus ad basin dense 
confluenter punctatis. Long. 33, lat. 2 m.m. 
The only individual I have seen is an immature female. It is extremely close 
to H. medialis, but is more regularly oval in form, and shows some slight distinctions 
of colour and sculpture. 
North America, (Lake Superior). 213. 
401. Hydroporus medialis, Lee., M.C.—Ovalis, sine pubescentia, nitidus, abdomine 
pectoreque nigris, capite, thorace, antennis pedibusque testaceis, elytris pallidis 
plaga magna vaga fusca, crebre sat fortiter sequaliter punctatis, stria discoidali pune- 
torum impressa obsoleta ; coxis posterioribus punctis magnis et profundis fere densis, 
abdominis lateribus ad basin fortiter confluenter punctatis. Long. 33, lat. 1% m.m. 
The sexual differences are very slight. The male front tarsi are slightly dilated, 
and the internal claw is a little thicker than the outer. 
North America, (San Diego, California). 212. 
402. Ilydroporus ovoideus, Lec., M.C.—Ovalis, sine pubescentia, nitidus, abdomine 
pectoreque nigris, supra rufescens ; elytris pallidioribus sutura angustissime nigra, 
sat crebre et fortiter fere sequaliter punctatis; corpore subtus nitido, coxis postert- 
oribus sat crebre punctatis. Long. 32 lat, 2 m.m. 
I have seen only a single specimen of this species which is closely allied to 
Hyphydrus marklini (No. 396), but is a little broader and has the punctuation of the 
elytra and thorax more sparing: the two may, however, perhaps prove to be one 
species. 
North America, (Lake Superior). 210. 
403. Hydroporus nubilus, Lee., M.C.—Ovalis, angustulus, elongatus, fere sine 
pubescentia, sat nitidus, testaceus, pectore abdomineque nigris ; elytris signaturis 
coalescentibus plus minusve distinctis fuscis, crebre cequaliter fere subtiliter punc- 
tatis, coxis posterioribus crebre punctatis. Long. 43, lat. 22 m.m. 
The male has the front and middle tarsi distinctly dilated, and the internal claw 
on the front ones thickened. The female is not quite so shining as the male, and 
has the middle tarsi elongate and much compressed. 
North America, (Massachusetts, Philadelphia, Texas, Colorado). 208. 
404, Coelambus infuscatus, n. sp.—Oblongo-ovalis, fere sine pubescentia, testaceus, 
abdomine pectoreque nigris, elytris signaturis magnis coalescentibus fuscis, dense, 
