On Aquatie Carnworous Coleoptera or Dytiscide. 587 
the individuals from Madagascar: but I cannot at present find other marks to 
distinguish them. In some individuals the internal stria of the elytra becomes 
obsolete in front. 
Madagascar ; Senegal, 703. 
873. Copelatus erichsoni, Guer., M.C.—Ovalis, haud angustus, subdepressus, 
nitidus, piceo-rufus, thorace elytrisque nigricantibus, illo versus angulos anteriores 
rufescente, his fascia basali, et vitta intra-laterali cum macula ante-apicali fere 
conjuncta, testaceis, antennis pedibusque rufis; thorace strigulis brevibus numerosis ; 
elytris striis decem per-profundis alternis posterius paulo brevioribus, aliaque mar- 
ginali valde abbreviata. Long. 64, lat. 34 m.m. 
The male has the front and middle tarsi a little dilated, and the front tibiz a 
little curved at the base, and a little bisinuate internally below the knee; the 
female does not depart in sculpture from the male. The species is closely allied to 
Copelatus polystrigus, but is readily distinguished by the greater sculpture of the 
thorax, and the very deep strize of the elytra. 
Abyssinia. 704. 
874. Copelatus obscurus, n. sp.—Ovalis, subdepressus, piceus, capite, prothorace 
elytrorumque apice dilutioribus, antennis pedibusque rufis; prothorace strigulis 
subtilioribus brevioribusque, in disco levigato ; elytris striis decem sat suibtlibus, 
2? quam ceteris paulo brevioribus, aliaque marginali anterius abbreviata, Long. 54, 
lat. 22 m.m. 
This species 1s closely allied to Dytiscus posticatus (No. 875), but is smaller than 
its smallest forms, and has the scratches of the thorax more reduced ; on the other 
hand the alternate strize of the elytra are less abbreviate behind, and the colour 
seems more obscure; though on this latter point I do not feel very sure as I have 
seen but a single female in rather bad condition; there are no traces of any fine 
scratches on the elytra of this species. 
Amazons, (Rio Sappo, found in water standing in a canoe by Prof. Traill, 21st November, 1874). 637. 
875. Dytiscus posticatus, Fab., Copelatus posticatus, M.C.~—Ovalis, subdepressus, 
nitidus, piceus, capite piceo-rufo, prothoracis lateribus elytrorumque basi ferrugineis, 
his apice (seepiusque macula laterali) dilutiore vel rufescente; prothorace strigulis 
distinctis sat numerosis fere equaliter distributis; elytris striis decem sat subtilibus, 
alternis posterius evidenter abbreviatis, 2* quam ceteris brevioribus, aliaque marginali, 
anterius abbreviata. Long. 6, lat. 83 m.m. 
The male has the front and middle tarsi distinctly dilated, the front tibise are 
TRANS, ROY. DUB. SOC., N.S., VOL. II. 4G 
