On Aquatic Carnivorous Coleoptcra or JJijtiscidw. 435 



subtilissime punctatus, subtus opacus, densissime subtilissime reticulatus. Long. 

 4i, lat. 2i m.m. 



The sexes are scarcely distinguishable externally. 



Northern Europe, and in the Alps and Pyrenees : Sardinia, (Damry) ; extends as far as 69° North in 

 Finland ; Arctic Asia, (Sahlberg) ; Pankong Valley, Thibet, (Stolickza). 



I have an individual from an old collection, indicated as being from North America : and the species is 

 stated by Schaum to exist in Unalaschka, and Lake Superior. 227. 



494. Hydroporus striatellus, Lee, M.C. — Ovalis, sat latus, densius breviter 

 evidenter pubescens, opacus, subtus niger, supra fusculus, capite thorace elytrisque 

 signaturis variabilibus testaceis, antennis pedibusque rufis, plus minusve infuscatis ; 

 corpore dense subtilissime punctulato, elytris versus siituram striis impressis 

 distinctis. Long. 4, lat. 2 m.m. 



In the male the front and middle tarsi are rather broader than in the female, and 

 the claws of the front ones are more developed, the sides of the thorax are oblique, 

 being not at all contracted behind the middle, so that the hind angles are obtuse 

 but scarcely rounded, while in the female the sides are more curved, and the hind 

 angles quite rounded. 



California: Mexico. 26G. 



L 41.— Genus IIYDBOPORUS. 



The mesosternal fork is connected with the intercoxal process of the metasternum ; 

 there is no ligula on the inner face of the wing-case ; the posterior portion of the 

 epipleura is narrow, and the genicular area is not limited externally by a raised line. 



The species are very numerous, (about 150) and their arrangement in a natural 

 manner by no means easy.* I have adopted nine groups as follows. 



* In addition to those of which the characters are here given, the following may with more or less 

 certainty be assigned to the genus : — Hydrocoptus dauricus, Motsch. (No. 1331, Imj. op.) ? No. 529 var. • 



Eastern Siberia. — Hydrocoptus mixtus, Motsch. (No. 1332) 1 near No. 612; Kirghiz Steppes. 



Hydrocoptus obscuripes, Motsch. (No. 1333) ; Eastern Siberia. — Hydroporus aberrans, Glk. (No. 13o7), 

 gen. dub. ; Java. — Hydroporus basinotatus, Eeiche (No. 1344), near No. 569; Tangiers. — Hydropoi-us 

 bifidus, Say (No. 1346) "? near No. 525; Mexico. — Hydroporus caliginosus, Lee. (No. 13-18), near 



No. 553 ; North America. — Hydroporus compunctus, Woll. (No. 1353) near No. 569 ; Canary Islands. 



Hydroporus contractulus, Mann. (No. 1354) 1 near No. 602 ; N orth America. — Hydroporus cribratellus, 

 Fairm. (No. 1356), Algeria. — Hydroporus cyprius, Regt. (No. 1357) near No. 564 ; Cyprus. — Hydroporus 

 decemsignatus, Clk. (No. 1358), near No. 527; Mexico. — Hydroporus delectus, Woll. (No. 1359) ? No. 

 547 var. ; Canary Islands. — HycU-opoiiis dichrous, Melsh. (No. 1361), near No. 627; North America. — 

 Hydroporus discicollis, Say (No. 1362) ; North America. — Hydroporus dorsoplagiatus, Fairm. (No. 1364^, 

 near No. 550 ; Algeria. — Hydroporus exilis. Boh. (No. 1369), gen. dub. ; Caffraria. — Hydroporus gracilis, 

 Wehncke (No. 1373) near No. 604; Spain. — Hydropoi-us habclmanni, Wehncke (No. 1375) ; Europe. — 

 Hydroporus hottentottus, Har. (No. 1377), gen. dub. ; Caffraria. — Hydroporus humilis, Klug. (No. 1378) 

 1 No. 569 var. ; Sinai. — Hydroporus ignotus, Muls. (No. 1379) ? No. 544 var. ; France. — Hydroporus 

 incrassatus, Th. (No. 1381) ; Sweden. — Hydroporus kingi, Clk. (No. 1388), near No. 641 ; Mexico. — 

 Hydroporus laccophOinus, Lee. (No. 1389), North America. — Hydropoi-us latebrosus, Lee. (No. 1391) , 



TRA^3. EOT. DDB. SOC, N.S., VOL. II. 3 I, 



