514 On Aquatic Carnivorous Coleoptera or Dytiscidm. 



and darker in colour, and the upper surface is still more destitute of reticulation, 

 and the anterior tarsi of the male are more slender. 



A series of about twelve specimens shows very little variation. 



North America, (Hudson's Bay). 1155. 



710. Agabus anthracinus, Mann., Bull. Mosc. 1852, II, p. 304. — Ovalis, parum 

 latus, sat convexus, subnitidus, niger, .supra senescens, antennis pedibusque rufis, 

 plus minusve infuscatis, his femoribus picescentibus ; supra undique crebrius pro- 

 funde reticulatus, reticulis elytrorum (prsesertim versus apicem) fere transversis. 

 Long. 7 2, lat. 4 m.m. 



The male has the basal joints of the front and middle tar.si, a good deal incrassate, 

 but much compressed, and furnished beneath with moderately large palettes ; the 

 anterior claws are rather elongate and nearly straight, a little unequal, the front 

 one being rather longer than the other, and dilated beneath : the terminal joint of 

 the middle tarsus and its claws are slender. The female resembles the male in 

 sculpture. 



The species is allied to Dytiscus arcticus (No. 736), although it is so different in 

 the colour : its sculpture although very remarkable is similar to that of D. arcticus 

 except in being deeper. 



North America, (Hudson's Bay, Canada, Sitkha). 799. 



711. Agabus subfuscatus, n. sp. — Ovalis, sat nitidus, niger, prothorace subaenes- 

 cente, elytris fuscescentibus, basi lateribusque vage testaceis, antennis pedibusque 

 rufo-testaceis ; elytris nullo modo reticulatis, parce subtilissime punctulatis. 

 Long. 7? lat. 4 m.m. 



The male has the front and middle tarsi with the basal joints slightly thickened 

 and furnished beneath with short hairs which bear below distinct palettes ; the 

 claws of the front feet are rather elongate and nearly simple. The female differs 

 only by the simple tarsi. The species resembles excessively Dytiscus congener (No. 

 706) but the sculpture of the elytra is slightly different, there being no trace of any 

 reticulation, the hind coxse are distinctly larger, and the prosternal process slightly 

 more developed, and the supra-articular border is much wider. It is equally 

 similar to Dytiscus paludosus (No. 680) but has the mesosternal groove more 

 elongate, and the male tarsi bear distinct palettes. 



It is possible that this species and not No. 708 may be the Colymbetes ambiguus 

 Say. 



North America, (Massachusetts). 749. 



