On Aquatic Cca-iiivorous Coleoptera or DijtiscidcB. 441 



The male has the front and middle tarsi a little broader than in the female ; 

 there is extremely little difference in the sculpture of the two sexes. 

 • This species seems to be a very distinct one, the thorax has the sides without 

 any curve, the pubescence of the upper surface is shorter than in the allies, the 

 sexual differences are slight, and the coxal lines at the apex are a good deal turned 

 outwards. The colour is bright, the yellow markings on the elytra are extensive, 

 but are much broken up by longitudinal interruptions of the dark colour. 



Canada, (Coll. Murray). 1143. 



508. Hydroporus clypealis, n. sp. — Ovalis, sat latus, tenuiter hand dense 

 pubescens, ferrugineus, prothorace anterius et posterius elytrisque nigricantibus, 

 his testaceo-signatis ; prothorace tenuiter marginato ; coxis posterioribus fortiter vix 

 dense punctatis. Long. 4, lat. 2t m.m. 



In the male the front and middle tarsi are moderately dilated, and the claws of 

 the anterior ones are a good deal more developed than in the female, and are 

 unequal, the front one being a good deal thicker and shorter than the hind one : 

 the upper surface is quite shining, the punctuation of the elytra being distinct and 

 not dense, while in the female the surface is quite dull and the sculpture obsolete. 



The male of this species is easily distinguished from that of Hydropoms 

 undulatus (No. 503), but the females are very similar; the antennae are nearly 

 entirely red, however, in the present species, and the punctuation of the hind coxae 

 is coarser and not so dense. 



North America, (Massachusetts). 275. 



509. Hydroporus anticus, n. sp. — Ovalis, rufo-testaceus, prothorace basi medio 

 maculaque in margine anteriore elytrisque nigricantibus, his signaturis conspicuis 

 testaceis ; prothorace tenuiter marginato ; coxis posterioribus fortiter minus dense 

 punctatis. Long. 4, lat. 2| m.m. 



I have seen only females of this species, they have the upper surface dull and its 

 punctuation obsolete. The coxal lines are in this insect distinctly curved outwards 

 at the extremity. 



North America, (Pennsylvania, Louisiana). 276. 



510. Hydroporus consimilis, Lee, M.C. — Ovalis, minus latus, evidenter pubescens, 

 dense punctatus fere opacus, Isete ferrugineus, prothorace anterius et posterius 

 elytrisque nigricantibus, his signaturis conspicuis testaceis ; prothorace tenuiter 

 marginato ; elytris dense minus profunde punctatis ; coxis posterioribus fortiter, fere 

 dense punctatis. Long. 4}, lat. vix 2h m.m. 



