350 On Aquatic Carnivorous Coleoptera or Dyliscida. 



260. Bidessus discretus, n. sp. — Oblongo-ovalis, brevis, sat convexus, fere sine 

 pubescentia rufo-testaceus, elytris fuscis, signaturis magnis pallide testaceis, 

 abdomine plus minusve iiifuscato ; elytris crebrius fortiter punctatis, prothorace 

 minus distincte punctato ; coxis posterioribus fortiter punctatis. Long. 2, lat. 

 li m.ni. 



The male is shining and has the front and middle tarsi distinctly dilated : of the 

 female there are two forms, one similar to the male in sculpture, the other dull and 

 with the punctuation of the upper surface more obsolete. The plica (or basal im- 

 pression) on the elytra is very distinct, and is about as long as that on the thorax. 

 The colour of the elytra is somewhat variable ; the base is fuscous, but a slight 

 distance from it there is a very broad pale yellow band, which externally reaches 

 as tar forward as the shoulder, and internally is interrupted at the suture, across the 

 middle there is a dark band which indeed extends nearly to the apex, except that 

 there is a very large subapical mark ; the yellow colour, however, at the base and 

 apex is sometimes more extensive owing to the comparative obliteration of the 

 dark marks. 



North America, (Texas, Belfrage). 1130. 



261. Dytiscus unistriatus, Schranck, Bydroporus unistriatiis, M.C. — Ovalis, 

 piceus,vel fuscus,vel rufescens, thorace rufescente, subtiliter sed distincte jiubescens, 

 subnitidus; elytris crebre, distincte, basi sat fortiter punctatis, stria sutunili abbreviata. 

 Lonof. 2, lat. 1 m.m. 



The male has the front and middle tarsi distinctly dilated. There are two forms 

 of the female, one is quite dull, and has the punctuation quite obsolete ; the other 

 difters but little from the male so far as the sculpture is concerned. 



This is a very variable species, the colour is sometimes nearly black, with the 

 margins of the elytra, and an interrupted obscure basal fascia pale, the thorax being 

 nearly red : sometimes the general colour is of an obscure red with the suture 

 slightly darker. In Finland is found a variety which is more shining and less 

 pubescent, and has the punctures of the elytra more distinct and distant : I have 

 seen from Lanaeken, in Belgium, two specimens closely approaching this Finland 

 form. 



Europe, from Lapland to Corsica ; Britain, Belgium, France, Germany. 1 1 G. 



262. Hydroporus goudotii. Lap., M.C. — Ovalis, nitidus, tenuissime pubescens, 

 antennis, pedibus, capite thoraceque testaceis, hoc basi infuscato ; elytris fusco- 

 testaceis, signaturis externis indeterminate pallidioribus; crebre punctatis, punctis ad 

 basin versus suturam f ortioribus ; pectore abdomineque piceis. Long. 1 1, lat. 1 ni.m. 



I do not see any characters by which the male can be distinguished from the 



