28 ADEPHAGA. 
finer and more obsolete; the under surface is densely and finely rugose, the sculpture 
here being rougher than in H. wquinoctialis. In one of the individuals before me the 
Wing-cases have no yellow marks; in the other two there is a large basal and several 
other more indefinite and smaller marks. The sexes are very similar; but the male has 
the front and middle tarsi a little broader, and the claws of the anterior feet a little 
longer and stouter than the female, and in this latter sex the thorax at the base is just 
perceptibly less broad. 
HYDROPORUS. 
Hydroporus, Clairv. Ent. Helv. ii. p. 182 (1806) ; Aubé, Spec. Gén. vi. p.468; Sharp, Trans. Roy. 
Dubl. Soc. n. s. ii. p. 868. 
This is the most extensive of the genera of Dysticide, and comprises upwards of 150 
species; it is nearly confined to the Palearctic and Nearctic regions, where numerous 
species occur in high latitudes; one or two are confined to the Rio de la Plata and 
Chili, and one or two to Southern Africa. 
1. Hydroporus infaustus. 
Hydroporus infaustus, Clk. Ann. & Mag. Nat. Hist. ser. 3, x. p. 179’. 
Hab. Mexico, between Nopaluca and Vera Cruz (Truqui'). 
The description of this species was made from a single individual; and I am inclined 
to think the name is probably only a synonym of Hydroporus striatellus; this, 
however, must remain uncertain till the fauna of Mexico is more completely known 
to us, Clark’s unique type having been, I believe, lost. 
2. Hydroporus mexicanus. 
Hydroporus mexicanus, Sharp, Trans. Roy. Dubl. Soc. n. s. ii. p. 447°. 
Hab. Mexico 1. 
Var. minor, elytris immaculatis. 
Hab. Mexico, Jalapa (Hoge). 
The unique individual taken by Hoge is a female, and, although considerably smaller 
than my original specimens, does not appear to differ in other important respects. 
3. Hydroporus roffi. 
Hydroporus roffi, Clk. Ann. & Mag. Nat. Hist. ser. 3, x. p. 176%. 
Hab. Mexico (Truqui'). 
If I am right in identifying two individuals in my collection with Clark’s description, 
this species is distinct from H. decemsignatus by its rather smaller size and shorter form, 
by its more distinctly punctured head and thorax, by the interposition of a number of 
punctures between the sutural and discoidal series on the wing-cases, and by its shorter 
