FAM. EMPIDID/E 281 
4. Second section of costa subequal to third, second vein not sinuous; 
anterior legs and hind tibiz brown, the middle tibize of male not 
deformed ; stalk of male palpi shorter than proboscis, palpi of female 
Wwbite. (Alas D. C.-dda, Wyo.) . ov Sive eco muc ciet ? Ts BIMAGUEATA, Loew; 
Second section of costa longer than third, second vein sinuous; legs 
almost wholly black, the middle tibiz of male with stout thumb-like 
process before apex; stalk of male palpi slender and as long as 
proboscis, palpi of female black. (Wash., Ida.) . 
«4s sto d. TACOMA: OV. Sp; (1) 
5. Dark cross-bands of wings united in front. (N. H., W. Va., Col., Ore., 
ANashe cer re Uere uestem ievtedi-s c v QUU Tu VARIBENNIS, Coquillett. 
Dark cross-bands separated, at least through submarginal cell. . . . . . . . . . . . 6. 
D EPUDIBUFHUDENSHNOP, Quos Mera QoPIUP LIN EQ CM Ed M LU I Eae Ere M o i fa 
Propleure pruinose; wingsslender,the marginalhairsshort . . . . . . . . . . . . &8. 
7- WIbBS slender, fringe.short: (Cal) 9459-0 Sese s caudis uv. T. PSELIOPHORA; TlOY. Sp.(2). 
Wings blunt, fringe longer than crossveins. (Mexico) . . . . . . T.cirira, Melander. 
8. Hyaline middle band of wings with parallel sides; palpi blackish; 
ppbIButbulsbeHn i CN PACK ee qu INN I oM ss V rq riu ie 
Hyaline band curved or angulate at fourth vein; occiput largely 
BIniDGsB Oc coc MT da qc uere d etuer se 
(1) Tachydromia Tacoma, nov. sp. — Length 3.3 mm. | Occiput gray pruinose except below where it becomes 
shining jet black, its upper bristles black, its lower ones long and white; front glistening black, its sides parallel, ocelli 
minute : antennae blackish, the outer joint short ovate, with terminal arista four times the length of the antenne: palpi 
of c longer than the proboscis, slender, yellow and tapering on the proximal two-thirds, then suddenly widened, jet black, 
and with a deep and broad emargination on the outside; palpi of O as long as the proboscis, slender, black and black- 
hairy; proboscis one-half the height of the head, vertical. "Thorax slender, jet black, the humeri prominent; propleurz 
and posterior half of the metapleurze white-pruinose, scutellum and supraalar spot cinereous; humeral bristles wanting, 
dorsocentral and a single row of acrostichal setulee minute, two supraalar macrocheetee, four scutéellar bristles. — Basal hal 
of the abdominal segments lightly cinereous, apical half jet black; hypopygium small, with long loose black curved hairs 
Halteres with white knob ; calypteres blackish, fringed with six dusky hairs. Legs jet black, the front coxee white-pruinose 
anteriorly and tipped with a bunch of white hairs; front femora robust, pollinose beneath, middle femora C with a series 
of long bristles on the anterior flexor edge; the middle tibize inside with a prominent thumb-like setulose preapical pro- 
jection and on the extensor side with a setigerous tubercle opposite. Wings with two brown crossbands jointed in the 
marginal cell, the second vein sinuous, arching forward at the central hyaline fascia and then bending backward so that 
the marginal cell before its apex is as broad as the submarginal cell, the second section of the costa about one and one- 
half times as long as the third, the third and fourth veins subparallel, the fourth vein curving forward at the very end 
of the wing, the distance between the crossveins three times as long as the posterior crossvein, fifth vein nearly 
straight, terminating at the end of the hyaline fascia, its sections proportioned nearly two to one. 
Many specimens from Mount Rainier, Washington, collected by Messrs. Dyar and Caudell and by the author, and 
one specimen from Moscow Mountain, Idaho. The flies are to found running over the large boulders in the rivulets and 
on the rocky cliffs close to the timber-line and have been taken on tents in camp at Paradise Park. The specific name is 
suggested by the Indian name for the large snow-capped mountain which is the home of these flies. 
(2 Tachydremia pseliophora, nov. sp. — Male. Length 2.1 mm. Polished black, the upper occiput very 
thinly pollinose, the pectus above pruinose. Front shining, face obliterated by the contiguity of the eyes; basal joint of 
antennz yellow, outer joint brown, short-ovate, palpi blackish, narrow, tipped with a black seta. Abdomen shining, pygi- 
dium large, the left valve prominent, curved and finger-like, last ventral segment fringed with long black hairs. Coxe 
yellow, front femora yellow becoming brown on distal one-half, front tibize thicker than the others and marked with two 
black rings, front tarsi yellow, the last joint black, middle brownish, the femora paler at base and furnished with two flexor 
rows of black setulz, those at the base of the posterior row longest, hind femora and tibia blackish, paler at base, the tarsi 
brownish.  Halteres white. Wings elongate oval, marked with two broad smoky bands, veins uniformly brown, middle 
hyaline stripe angled, costal sections two to four proportioned 5 : 3 : 1, second vein straight to near the gently curving end, 
first posterior cell narrow, sections of fourth vein 2 : 1 : 4.5, last section of fifth vein curved and separating the dark and 
light stripes. 
Female. Front tibiz uniformly yellowish brown. 
Four specimens, Los Cerrites, California, April 3, 1915, collected by M. C. Van Duzee. 
