44 4 On Aquatic Carnivorous Colcoptera or Di/tisciclcB. 



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., IM.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. Is 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 epipleuroe 

 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, Aube, M.C. — Ovalis, convexiusculus, parce subtilius 

 pubesccns, sat nitidus, la;te feriugineus, 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, a], 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. 



Noi-th America, (Texas ; "Western and Southern States sec. Crotch). 294. 



520. Hydroporus mixtu.s, Lee, M.C. — Ovalis, sat elongatus, parcius pubes- 

 cens, nitidulus, rufo-testaceus, elytris obscurioribus sifjnaturis ma<2:nis rufo- 

 testaceis, fortiter sat crebre punctatis ; prothorace minus tenuiter marginato ; coxis 

 posterioribus fortiter sat crebre punctatis. Long. 4^-, lat. 2} m.m. 



I have seen only one good individual of this species ; the coxal lines are rather 

 curved in front, and at the apex are di.stinctly divergent. 



North America. (Nebraska). 282. 



