1878. ] , 597 : {LeConte. 
and feet tinged with piceous. Prothorax with sides oblique, finely mar- 
gined ; apical and basal rows of punctures strongly marked. Elytra with 
the rows of punctures strongly marked. Prosternum acutely carinate ; me- 
sosternum deeply emarginate ; front and middle thighs punctured and ru- 
gose ; hind tibiz smooth, with a few small punctures at the inner margin 
and some larger ones along the outer margin. Length 9 mm.; 35 inch. 
3S Smooth but not polished ; claws of front tarsi long, not toothed, curv- 
ed only near the tip. 
2 Scarcely perceptibly punctulate ; claws of front tarsi not so long, and 
regularly curved. 
Lake Superior; the elytra vary from brown to black, with 
only the edge brownish. The form is exactly as in G. 
parallelus, from which it differs greatly by the other charac- 
ters. 
11. Hydrobius feminalis. Sub-ovate, convex, blackish piceous, 
sides of prothorax and elytra and beneath paler. Head and prothorax 
sparsely punctulate, elytra finely not densely punctured, sutural stria deep, 
extending from the middle to the tip. Length 2 mm.; .08 inch. 
Detroit. This species is less oval than the others of the 
same size in our fauna, and is somewhat narrower behind 
than in front; it is free from metallic lustre. The pros- 
ternum and mesosternum are not prominent, and the thighs 
are punctulate and pubescent from-the base nearly to the 
knees. It therefore belongs to the genuine Hydrobii, and is 
allied to the two following Californian species. 
12. Hydrobius castaneus. Oval, convex, shining brown, beneath 
piceous. Head prothorax and elytra finely, moderately densely punctured, 
the latter a little more strongly ; sutural stria deep, extending from the mid- 
dle to the tip. Length 2.5 mm.; .10 inch. 
Lake Tahoe, Cal.; Mr. Crotch. The pro- and mesoster- 
num are not carinated, and the thighs are punctulate and 
pubescent except near the knees. 
13. Hydrobius cuspidatus. Oval, more elongate and somewhat 
less convex ; blackish piceous, paler at the sides of the head and prothorax, 
also along the basal and apical margins of the latter; finely punctured, 
rather more strongly upon the elytra, with here and there indistinct traces 
of rows. Length 3.4 mm.; .14 inch. 
Lake Tahoe, Cal.; Mr. Crotch. The prosternum is not 
earinate ; the mesosternum is strongly carinate, with the an- 
terior angle rectangular and slightly cuspidate. The under 
