On Aquatic Carnivorous Coleoptera or Dytiscida. 435 
subtilissime punctatus, subtus opacus, densissime subtilissime reticulatus. Long. 
43, lat. 24 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 testaccis, antennis pedibusque rufis, plus minusve infuscatis ; 
corpore dense subtilissime punctulato, elytris versus suturam striis impressis 
distinctis. Long. 4, lat. 2 ra.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. 266. 
I. 41.—Genus HYDROPORUS. 
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. 
* Tn addition to those of which the characters are here given, the following may with more or less 
certainty be assigned to the genus :—Hydrocopius dauricus, Motsch. (No. 1331, huj. op.) ? No. 529 var. ; 
Eastern Siberia.—Hydrocoptus mixtus, Motsch. (No. 1332) ? near No. 612; Kirghiz Steppes.— 
Hydrocoptus obscuripes, Motsch. (No. 1333) ; Eastern Siberia.—Hydroperus aberrans, Clk. (No. 1357), 
gen. dub. ; Java.—Hydroporus basinotatus, Reiche (No. 1344), near No. 569; Tangiers.—Hydroporus 
bifidus, Say (No. 1346) ? near No. 525; Mexico.—Hydroporus caliginosus, Lee. (No. 1348), near 
No. 553; North America.—Hydroporus compunctus, Woll. (No. 1353) near No. 569 ; Canary Islands.— 
Hydroporus contractulus, Mann. (No. 1354) ? near No. 602 ; North 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. 
047 var. ; Canary Islands.—Hydroporus 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.—Hydroporus habelmanni, Wehncke (No. 1375) ; Europe.— 
Hydroporus hottentottus, Har. (No. 1377), gen. dub. ; Caffraria.—Hydroporus humilis, Klug. (No. 1378) 
1 No. 569 var. ; SinaiiHydroporus ignotus, Muls. (No. 1379) ? No. 544 var. ; France.—Hydroporus 
incrassatus, Th. (No. 1381) ; Sweden.—Hydroporus kingi, Clk. (No. 1388), near No. 641; Mexico.— 
Hydroporus laccophilinus, Lec. (No. 1389), North America.—Hydroporus latebrosus, Lec. (No. 1321) ; 
TRANS. ROY. DUB. SOC., N.S., VOL. Il. 38L 
