COLEOPTERA— HTDROPHILIDiE. 511 



tliere is mucli doubt. The elytron is pretty well arched, equal nearly to 

 the tip, then rapidly rounded off, indicating an ovate beetle with the shape 

 of a Hydrobius or a shorter insect, and of about the size oiHelophorus lineatus 

 Say. Eight fixintly impressed unimpunctured striae are visible, the outer 

 one, and to some extent the one next it, deeper ; these two xinite close to the 

 tip, curving strongly apically ; the next two curve slightly near their ex- 

 tremity, but ai"e much shorter, not reaching the fourth stria from the suture, 

 which, like the remaining three, pursues a straight course to the seventh 

 stria. The surface between the striae is nearly smooth, jjiceous. 



Length of fragment, 2.4""; breadth of elytron, 1.35""°; distance apart 

 of the stria?., 0.15"™. 



Nicola River, below main coal seam, British Columbia. One specimen, 

 No. 57 (Dr. G. M. Dawson). 



HYDROBIUS Leach. 

 Hydkobius decineratus. 



PI. 8, Fig. 27. 

 Hydrobim decineratus Scndd., Bull. U. S. Geol. Geogr. Surv. Terr., IV, 761 (1878). 



A single specimen exhibits the dorsal surface, but with part of the thorax 

 gone. It represents a species a very little larger than H. fuscipes Curt, of 

 California, and is apparently allied to it, though slenderer ; the head and 

 eyes are as in that species; the thorax shorter and the elytra longer and 

 more tapering at the tips, the extremities of which, however, are not pre- 

 served ; they are furnished with eight delicate strias, in which the punctures 

 are scarcely perceptible even when magnified ; the surface otherwise ap- 

 pears to be smooth, but is not well preserved. The scutellum is as in the 

 recent species mentioned. 



Length of body, 7.5"" ; of elytra, 4.75"" ; breadth of body, 3.6"". 



Green River, Wyoming. One specimen. No. 4007. 



Hydrobius confixus. 



PI. 7, Fig. 25. 

 A single elytron has been found, perfectly flat, with nearly parallel 

 sides and a bluntly pointed apex. It shows place for a minute scutellum, 

 the surface is smooth, but marked by nine parallel, equidistant, slightly 



