378 



PSYCHE. 



[July 1890. 



Hydrophorus philombrius, n. sp. $. 



Length 3.5 mm. ; length of wing 4 mm. 



Dull olive green. Face bright metallic 

 green, covered with white dust, which scarce- 

 ly dims the brilliant ground color, except on 

 the oral margin, where it is aggregated to 

 form two spots, one on each side abutting on 

 the orbit. Cheeks and palpi black, clothed 

 with short appressed yellow pubescence; the 

 pubescence on the eyes short and silvery 

 white. Antennae black, pubescence on the 

 third joint white, tip of the robust arista pale. 

 Front and occiput of a blackish ground col- 

 or, covered with glistening white dust which 

 gives them a frosted appearance ; cilia of the 

 superior orbit black; those of the inferior or- 

 bit glistening white, but becoming tawny 

 near the oral orifice. Thorax, scutellum and 

 abdomen covered with the same frost-like 

 dust as the front; as this dust, which con- 

 sists of microscopic scales, is wanting about 

 the insertion of each seta, the surface has a 

 spotted appearance. The disk of the thoracic 

 dorsum is crossed by four longitudinal shin- 

 ing purple bands, the outer pair being slight- 

 ly broader than the inner; the spaces be- 

 tween these bands are vivid metallic green. 

 Scutellum bearing four rather long black 

 bristles; its median poition golden green, 

 the lateral portions coppery red. Pleurae 

 dull olive green, more olive brown towards 

 the insertions of the coxae. Tegulae honey- 

 yellow, with glistening white cilia. Abdo- 

 men olive green, in rear view more bluish; 

 the rows of impressed dots along the tergal 

 edges shining black ; the sparse hairs cover- 

 ing the terga of the basal segments and the 

 whole venter, glistening white; hypopygium 

 black, concealed, appendages not apparent 

 in my specimen. Legs and coxae covered 

 with white dust; the fore pair of legs black; 

 fore coxae dull metallic green, fore femora 

 incrassated in the usual manner and bearing 

 a few long spines at their bases on the under 

 side; on the hind face of the distal two thirds 

 of the fore tibiae there is an even comb of 

 stout black spines; apical claw distinctly 



marked though not acute; the distal half of 

 the fore tibiae and black tarsi with short and 

 dense white pubescence. Posterior femora 

 and tibiae slender, vivid metallic green; pos- 

 terior tarsi with white pubescence somewhat 

 more scattered than on the fore tarsi. Pulvilli 

 and empodia of all the feet white, fringed 

 with silvery hairs. Halteres bright honey 

 yellow, the base of the peduncle somewhat 

 infuscated. Wings long and narrow, costal 

 and posterior margins parallel, uniformly 

 grayish hyaline; veins black, becoming yel- 

 low near the insertion of the wings; third 

 and fourth longitudinal veins gently approxi- 

 mating near the tip of the wing, but again 

 diverging slightly at their juncture wit'h the 

 costa ; sixth longitudinal vein very short and 

 incomplete. 



Habitat: Milwaukee Co., Wis. 



This large and beautiful species seems 

 to be related to the Alaskan Hydro- 

 phorus innotahis^ Loew. It may be 

 distingtiished by the white dust on the 

 face and front, the glistening white cilia 

 of the inferior orbit, the vittate thoracic 

 dorsum, the bright yellow halteres and 

 the yellow bases of the nervures of the 

 wing. 



It is possible that the species which I 

 here call H. philofnbrlus is one of the 

 two species mentioned by Baron v. 

 Osten Sacken (Western Diptera p. 

 320.) '-One from Webber Lake, 

 Sierra Nevada (July 25) is allied 

 to H. innotatiiSy Loew from Sitka 

 (Monogr. 2 p. 212) in the coloring of 

 the face, the upper part of which is 

 greenish, and in other characters ; its 

 halteres, however, have a yellow, and 

 not aji infuscated knob. The other 

 species, taken near Santa Barbara (Jan- 

 uary 25), is easily distinguished by the 



