FAM. EMPIDIDJE 99 
the species are quite constant. The following table shows the variations in arrangement of the special 
bristles of the males. Females are more difficult to determine specifically than the males. The male 
of rufus is not known and the species is therefore omitted from the table. Both sexes of obscurus are 
dark, and the species is thus distinct from rufus. 
KEY TO THE SPECIES OF OREOGETON, BASED ON MALES 
I. Front tarsi with last two joints flat, black and densely fringed with 
Bus UMEN S UM NER NET RU ADU e terim : 2. 
brontiars/wihoubexpanded and pennate up |. ue o. MOS o eR ou 3 
2. Front tibize with dense cluster of black sete around tip . . . . . O.scorrreR, Coquillett. 
Front tibie notsetose around tip . . . . QW ONE Qi 0. Q CYMBAEBISTAU HOY. SD. (1). 
3. Some of the flexor sete near middle of middle tibize projecting far 
DNUUDNIHO SIUS Up. EI uM ue EL IT i RUE Ur ox. d 
Middle tibia nearly uniformly setose. . . . . . . . . . . .O. Basarrs, Loew. 
4. Third vein setulose above; central seta of middle femora stronger 
than the others; arista arising from above apex of antenna. . .  O. CAPNOPTERUS, nov. sp. (2). 
"Third vein bare, rarely with one or two setulae; more than one long 
seta under middle femora; aristaterminal . . . . . . . . . cr um hi 
5. Three or four oustanding setze: under middle femora; setze of middle 
COTYO-DÓIMPE. M lo SINUS UU EUM eU, : 6. 
About eight outstanding sete under middle femora; apical setze of 
middle coxe strong and blunt . . . . . . . . . . . . O. MITREPHORUS, nov. sp. (3). 
(1i) Oreogeton cymballista, nov. sp. — Male. Length 7; mm. Head and thorax black, base of abdomen 
pellucid yellow, remainder of abdomen piceous, legs, halteres and base of wings yellow. Last two joints of front 
tarsi flat, forming a black disk heavily fringed with black scale-like sete, last two joints of posterior tarsi likewise 
gantastingly black but not discoid, middle femora with five very long sete near middle beneath and with a comb 
of seven shorter setze toward knee along postero-flexor face, middle tibize bent, swollen at three-fifths their length 
where they bear a dense brush of flexor setule, also seriately setulóse toward knee beneath. along extensor side 
with five scattered long setze. Wings with reddish brown tinge. 
Holotype, Nelson, British Columbia, 17 July, 1910 (Melander). 
(2) Oreogeton capnopterus, nov. sp. — Male. Length 5.5 mm. Head black, thorax piceous, base of 
abdomen pellucid yellow, remainder of abdomen piceous, coxe and anterior legs yellow, hind legs brown, halteres with 
yellow. stalk and piceous knob, calypteres yellow. Last two joints of tarsi small, blackish but not contrasting with 
remainder of legs; central flexor seta of middle femora projecting beyond the others, the next one distal to it nearly 
as long, followed by six shorter not crowded sete toward the knee; middle tibize straight, finely and nearly uniformly 
setulose and with an extensor seta at three-fifths the length and a small pair near knee. Wings with blackish 
smoky tinge, third vein setulose above. "The arista is attached just above the apex of the antennz. 
Female. Occiput, front, third antennal joint and last two tarsal joints black, otherwise the insect is yellow, 
becoming brownish on posterior part of abdomen. Femora without specialized sete. Wings less infumated. Arista 
arising from tip of antenna. 
Four males, one female, south side of Mt. Rainier, Washington, August, 3500-5500 feet altitude (M elander); 
1 male Banff, Alberta, 12 July, 1922 (Garrett), in Canadian National Museum. 
(3) Oreogeton mitrephorus, nov. sp. (PI. 6, Fig. 51.) — Male. Length 5.5 mm. Head and thorax black, 
the sutures rufous, second and third segments of abdomen pellucid yellow, remainder piceous, legs, halteres, and 
base of wing yellowish. "Tarsi apically blackened, not expanded or pennate; middle coxe with five long blunt 
apical setz;; middle femora with about eight long flexor setze extending Ífrom before the middle almost to knee; 
middle tibiae almost straight, very slightly swollen at two-thirds the length where there are a few erect flexor setulae; 
one extensor seta near knee, two near middle and two near apex of middle tibize; apical setze of hind coxa small, 
hind femora more or less ciliate above and below. Wings with yellowish tinge, third vein not setulose. 
Female. Somewhat darker than male, only the second abdominal segment yellowish, coxc  piceous, femora more 
'or less brown, specialized leg bristles absent, third vein setulose. 
Five males, thirty-six females. Moscow Mountain and Lookout Mountain, Idaho, June-August (Melander). 
