68 Psyche [April 



shining green above, on the lower part with brown dust; palpi dark brown with 

 blackish hairs; antennae plain, small, first joint not elongated; underneath the 

 neck among the beard are rather numerous black bristles. Dorsum of thorax shin- 

 ing sealbrown, green before the scutellum and around the humeri, the acrostichal 

 and dorsocentral bristles very small and thin and rather numerous; even the hind- 

 most dorsocentral is thin and small; scutellars four; upper part of the pleura quite 

 pure green, lower part glaucous pruinose, few almost imperceptible microscopic 

 hairs on the upper part of the sternopleura; propleura with pale yellow hairs and one 

 black bristle; hal teres brown on the outer side of the knob; front coxae with fine 

 brownish hairs on the front side and small black spines at and above the tip; front 

 femora not much thickened, with a single row of bristles below along the middle, 

 about nine to twelve in number; near the tip below there is a prominence fol- 

 lowed by an excision; just back of the prominence is a close row of five stiff and 

 bluntly pointed spines; on the front tibia at the base is a slight lateral prominence 

 about opposite the excision in the femur, surmounted with minute spines; following 

 this to the apex is the usual row of small, rather erect spines; the effect of the 

 excision and both prominences is evidently to form an organ for holding the female. 

 The other legs of plain structure, except that the last two joints of the middle tarsi 

 are black and somewhat flattened, the fifth joint more so than the fourth. Wings of 

 moderate width, subhyaline, the veins black, with almost imperceptible spot on the 

 hind crossvein and another beyond (in one specimen these are considerably stronger). 

 Abdomen bright bluish green, glaucous only below and on the under part of the 

 sides; fourth sternite emarginate behind and the space occupied with a large black 

 organ which seems to end in a thin edge behind, quite different from most species. 

 Length, 4.2 mm.; of wing, 4.8. 



Female. The face is much wider, front and middle legs of plain structure. 

 Front femur below with loose brown hairs and toward the tip a small spine or two. 

 One female has the two spots of the wings more developed than the rest, but still 

 faint. Length, 4 mm., of vAng, 5.1 mm. 



Three males and two females, all taken at Brookings, S. D.; 

 three were captured in early spring of 1890. One male, Battle 

 Creek, Mich., summer of 1897. 



The female differs from that of magdalenoe in having much 

 shorter dorsocentrals, no row of spines under front femur, and 

 a brown spot on knob of hal teres. The male differs in the struc- 

 ture of the fore legs and in having a narrower face, as well as 

 in the smaller dorsocentrals. 



Hydrophorus pensus sp. nov. (fig. 7). 



Occiput shining green, only one pair of postverticals, the postorbitals about twelve 

 in number, extending down only about one-third the height of the eye; beard white; 

 no black bristles under the neck; cheek below the eye exceedingly narrow; front 

 dark brown, hardly at all greenish; face narrow above, smooth and brilliant blue, 

 below covered with white dust; palpi concolorous, with pale hairs; eyes with 



