On Aquatic- Carnivorous Coleoptera or Dijtiscidce. 587 



tlie individuals from Madagascar : but I cannot at present find other marks to 

 distinguish them. \n some individuals the internal stria of the elytra becomes 

 obsolete in front. 



Madagascar ; Senegal. 703. 



873. Copelatus erichsoni, Guer., M.C. — Ovalis, hand angustus, subdepressus, 

 nitidus, piceo-rufus, thorace elytrisque nigricantibus, ilio versus angulos anteriores 

 rufescente, his fascia basali, et vitta intra-laterali cum macula ante-apicali fere 

 conjuncta, testaceis, antennis pedibusque vufis; thorace strigulis brevibus numerosis; 

 eljtris striis decern pei'-profundis alternis posterius paulo brevioribus, aliaque mar- 

 ginali valde abbreviata. Long. 61, lat. 3i m.m. 



The male has the front and middle tarsi a little dilated, and the front tibiae 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 distinguislied by the greater scul^^ture of the 

 thorax, and the very deep striae of the elytra. 



Abyssinia. 704. 



874. Copelatus obscurus, n. sp. — Ovalis, subdejoressus, piceus, capite, prothorace 

 elytrorumque apice dilutioribus, antennis pedibusque rufis ; prothorace strigulis 

 subtilioribus brevioribusque, in disco Isevigato ; elytris striis decem sat suibtlibus, 

 2° quam ceteris paulo brevioribus, aliaque marginali anterius abbreviata. Long. 5i, 

 lat. 2? m.m. 



This species is closely allied to Dytiscus postieatus (No. 875), but is smaller than 

 its smallest forms, and has the scratches of the thorax more reduced ; on the other 

 hand the alternate strise 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 ti'aces of anv fine 

 scratches on the elytra of this species. 



Amazons, (Eio Sappo, foniul in Wiiter standing in a canoe by Prof. TraUl, "Jlst November, 1874). 637. 



875. Dytiscus postieatus. Fab., Copelatus postieatus, M.C. — Ovalis, subdepressus, 

 nitidus, piceus, capite piceo-rufo, prothoracis lateribus elytrorumque basi ferrugineis, 

 his apice (sajpiusque macula laterali) dilutioro vel rufescente ; prothorace strigulis 

 distinctis sat numerosis fere asqualiter distributis ; elytris striis decem sat subtilibus, 

 alternis posterius evidentcr abbreviatis, 2" quam ceteris brevioribus, aliaque marginali, 

 anterius abbreviata. Long. C, lat. o m.m. 



The male has the front and middle tarsi distinctly dilated, the front tibiaj are 



TBANS. ROY. DUB. SOC, N.S., VOL. 11. 4 G 



