444 On Aquatic Carnivorous Coleoptera or Dytiscide. 
The male is very finely and densely, but quite distinctly punctured, and is a little 
shining ; while the female is on the upper surface very densely and finely punctured 
and quite dull. The male has the front and middle tarsi a little dilated, the claws 
on the former thicker than in the female. 
In this species the coxal lines are rather strongly divergent at the apex. 
North America, (Texas ; Fort Laramie sec. Crotch). 286. 
518. Hydroporus striato-punctatus, Melsh., M.C.—Ovalis, sine pubescentia, sat 
nitidus, ferrugineus, thorace elytrisque infuscatis, illo medio lateribusque rufes- 
centibus, elytris signaturis humerali et apicali testaceis; coxis posterioribus 
profunde grosse punctatis ; elytris plagis duabus elongatis punctorum profundorum. 
Long. 3, lat. 1§ m.m. 
I do not know the sex of the individual described, which is badly preserved, and 
the only one I have seen; the species will be easily recognized by its peculiar 
punctuation; the third joint of the anterior tarsi is well developed and rather 
elongate ; the lateral margin of the thorax is moderately broad, and the epipleurze 
of the elytra although nearly impunctate, have their posterior portion less slender, 
than in most of the allies, and it is this character that has induced me to place the 
species near H. cimicoides and H. undulatus. 
North America ; (middle United States). 293. 
519. Hydroporus hybridus, Aubé, M.C.—Ovalis, convexiusculus, parce subtilius 
pubescens, sat nitidus, lete ferrugineus, prothorace basi medio elytrisque fuscis, 
his signaturis magnis rufis; prothorace omnino tenuiter marginato ; elytris minus 
crebre et minus fortiter punctatis ; coxis posterioribus nitidulis fere grosse punctatis. 
Long. 3s, lat. 2 m.m. 
The four specimens I have seen have the front tarsi slender. In this distinct 
species the coxal lines are much sinuate. 
North America, (Texas ; Western and Southern States sec. Crotch). 294. 
520. Hydroporus mixtus, Lec., M.C.—Ovalis, sat elongatus, parcius pubes- 
cens, nitidulus, rufo-testaceus, elytris obscurioribus signaturis magnis rufo- 
testaceis, fortiter sat crebre punctaus ; prothorace minus tenuiter marginato ; coxis 
posterioribus fortiter sat crebre punctatis. Long. 43, lat. 2t m.m. 
I have seen only one good individual of this species; the coxai lines are rather 
curved in front, and at the apex are distinctly divergent. 
North America. (Nebraska). 282. 
