514 On Aquatic Carmvorous Coleoptera or Dytiscide. 
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. Mose. 1852, II, p. 304.---Ovalis, parum 
latus, sat convexus, subnitidus, niger, supra zenescens, antennis pedibusque rufis, 
plus minusve infuscatis, his femoribus picescentibus ; supra undique crebrius pro- 
funde reticulatus, reticulis elytrorum (preesertim versus apicem) fere transversis. 
Long. 72, lat. 4 m.m. 
The male has the basal joints of the front and middle tarsi, 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 subzenes- 
cente, elytris fuscescentibus, basi lateribusque vage testaceis, antennis pedibusque 
rufo-testaceis; elytris nullo modo reticulatis, parce subtilissime punctulatis. 
Long. 72 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 coxee 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. 
