HYDROPHORUS. 213 



brownish dust. Antenna' entirely black. Front greenish-black, 

 opaque; seen in an oblique direction the covering of brown dust 

 upon it becomes perceptible, which otherwise is visible only on the 

 anterior margin. The ground-color of* the occiput is green and 

 but little covered with brownish-gray dust. The cilia of the upper 

 orbit are, as usual, black, the dense and hair-like cilia ou the late- 

 ral and inferior orbits, however, rusty-yellowish. The upper side 

 of the thorax metallic olive-brown ; the hindmost part with a 

 metallic-green reflection; the dust upon it is brown. Scutellum 

 with four bristles, vshinirig, rather green, though somewhat copper- 

 colored upon its middle. Pleura? and coxse with whitish dust. 

 Abdomen metallic-green, shining, especially on the sides ; the 

 short hair upon it is blackish, upon the sides of the first segment, 

 however, fallow-yellowish. Fore coxa3 on their front side with a 

 very short and delicate whitish pubescence, beset on the upper 

 half of their exterior side with a moderate number of compara- 

 tively long black bristles; a few of them are also at the tip. 

 Femora slender, green, with an almost imperceptible grayish 

 dust ; the fore femora as usual thickened towards their basis, and 

 beset on the under side near the basis with four or five rather long 

 thornlike bristles ; besides these there is, nearer to the anterior 

 margin, an apparently incomplete row of very short bristle-like 

 little hairs, which are but difficult to perceive. Tibia? dark green, 

 the foremost on their under side uniformly fringed with very short, 

 black thornlike bristles. Tarsi black. Cilia of the tegulae yel- 

 low. Halteres with a dusky yellow peduncle and with blackened 

 knob. "Wings very long, tinged with gray, not darker towards 

 the anterior margin and with veins which are black up to the ex- 

 treme root; the end of the third longitudinal vein is somewhat 

 curved backwards so as to converge distinctly towards the fourth 

 longitudinal vein; no dark spot is to be seen neither upon the 

 fourth longitudinal vein, nor upon the convexity, crossed by the 

 last segment of the fourth longitudinal vein. 



Bab. Sitka. (Sahlberg.) 



Observation. — Notwithstanding the not unimportant difference 

 in the coloring of the dust on the lower part of the face between 

 the two sexes described above, I have no doubt that both belong 

 together. From the other North American species, known to 

 me, 77. innotatus differs by the shining green color of the upper 

 part of the face. Among the European species it can only lie 



