0. infuscatus Sharp. 



"Oblongo-ovalis, fere sine pubescentia, testaceous, abdomine pectoreque nigris, 

 elytris signatures magnis coalescentibus fuscis, dense, aequaliter subtiliter punc- 

 tatis, serie punctorum impressa minus distincta; coxis posterioribus externe 

 minus crebre punctatis. Long. 5, lat. 2% mm." 



The above is Sharp's description of this species, which is unknown 

 to me in nature. The author goes on to remark that "This species is 

 readily distinguished from Hydroporus nubilus by its larger size, and 

 more finely and densely punctured elytra. I have seen only two in- 

 dividuals, both of which are females, one is shining, the other dull ; 

 the front tarsi are less compressed and are broader than in the corres- 

 ponding sex of nubilus." The very large size, together with the lo- 

 cality, will probably ensure the recognition of this species when it again 

 turns up. Only three species of our fauna unguicularis, impresso- 

 punctatus and orcgonus attain a length of 5 mm. 



C. nubilus Lee. 



Elongate oval, yellowish testaceous, antennae scarcely at all infuscate apically; 

 head pale, with or without a small transverse fuscous spot contiguous to the 

 thoracic margin; prothorax with small discal spot, the front and rear margins 

 scarcely darker; elytra with somewhat diffuse posteriorly confluent markings, 

 consisting of two subentire vittae near the suture, exterior to which are an- 

 terior and posterior spots representing two more abbreviated and interrupted 

 vittae. Elytral punctuation rather close and subequal throughout, the series 

 of coarser punctures nearly or quite absent. Beneath black moderately punc- 

 tate, epipleurae more closely and uniformly so than in patruelis. Front and 

 middle tarsi of male quite strongly dilated, the second joint perceptibly wider 

 than the first and third ; anterior claw of front tarsus (G?) a little shorter, 

 thicker and more strongly bent than its fellow. Length 4 to 4.4 mm. ; width 

 2 to 2.2 mm. 



A common and widely diffused species, occurring from New England 

 to Western Texas. Le Conte's type was from Fort Laramie and he 

 speaks of its occurrence also in Illinois. Specimens seen by me are 

 from Massachusetts (Blanchard) ; N. Y. ; Jeannett, Pa., Detroit, Mich. ; 

 McPherson Kans. ; Fedor, Tex. and El Paso, Tex. 



The elongate form, rather large size, evenly rather finely punctate 

 elytra, and pale head, form a combination of characters which separate 

 this species from all others except femoratus, from which males are 

 easily separable by the tabular characters. In the series of nubilus 

 before me, the few females are duller and finely alutaceous ; it is, how- 

 ever, not unlikely that shining females occur. 



C. femoratus Fall. 



This species is so exactly similar to nubilus as to be quite indistinguishable 

 except by reference to the femoral and tibial structure of the male. In this 

 sex all the femora are sinuate beneath near the knee, the margins strongly 

 laminate at apex. The tibiae are pedunculate at base, then suddenly widened 



