FAM. EMPIDID/E 273 
marginal cell long, first posterior cell narrow, with parallel veins; anal crossvein strong but the anal vein 
wanting ; calypteres fringed. 
Tyne species : T. »ubila, Meigen, by designation of Rondani in 1856.  Meigen in 1822 separated 
his species of Tachydromia into two groups, calling them A and B. In 1827 Macquart gave the name 
Platypalpus to group B, and in 183o Meigen called his group A Tachyfeza. It is from group A that Loew 
in 1863 separated his genus TacAista, which, containing the genotype of Tachydromia has become a 
synonym of that genus. ; 
The species of Tachypesa are often found running up and down the trunks of trees, especially such 
as have smooth bark. They carry their wings held against the abdomen and are loathe to take to flight. 
They can easily be collected by blowing them with a puff into the insect net. "The earlier stages are 
not known with certainty. 
KEY TO THE NEARCTIC SPECIES OF TACHYPEZA 
LI SOPIBHIG GDHUUGT o e WI UAE vei WI o EAM SLE, 
Mesopleurz largely or wholly shining, devoid of pollen 
2. Crossveins separated by three times their length ; front femora dark 
exteriorly and yellow interiorly, middle femora with basal tubercle T. prsrANs, nov. sp. (r). 
CrosveiDs separated bv tHelplowndenetho 5 oe SoMEeT cues Roe teu or 34 
3. Anterior femora Q'O yellow insideand dark outside . . ... . . . . .« « « - 4 «4 
Front femora c with black marks inside; crossveins not more smoky 
IDAIOBQQUBBALSUIDS - 20. e LIN RI Eom ro E oem oc sonst REM. M 
4. Crossveins more smoky than veins; hind femora blackish; middle 
femora brownish, in C with basal tooth, tibize with blackened apex, 
middle melunf OH -. o 46 UR s 25:5 V T. DISCIFERA, nov. sp. (2). 
(1) Tachypeza distans, nov. sp. — Male. Length3.2mm. Antenne reddish yellow, tipped with brown ; mouth 
parts yellowish, apical seta of palpi pale brown. "Thorax entirely pollinose. Abdomen subshining. Legs mainly yellow, 
marked with brown as follows, outside of front femora and tibize, subbasal and apical bands of middle tibi, apical half of 
hind femora except above, base and apex of hind tibiz and last joint of all tarsi ; front femora spongy pubescent below, 
flexor side of front tibize spongy pubescent in front and seriately black-setulose behind; middle femora with strong basal 
setigerous tubercle, near whichare several yellow setze.  Halteres yellow. Wings hyaline, first vein thickened, first posterior 
cell coarctate, as wide at middle as the marginal and submarginal cells together, hind crossvein remote from the anterior 
and very oblique, the distance between the two more than three times the length of either, last section of fifth vein two-thirds 
the length of the preceding. 
Holotype, Kamiac Butte, Washington (Melander). 
(2) Tachypeza discifera, nov.sp. (Pl. 4, Fig. 31). — Length 3 mm. Head and thorax uniformly opaque cine- 
reous; sides of front parallel; basal antennal joint yellow, the outer joint brown, rounded ovate, with terminal arista nearly 
four times the length of the antennz : palpi pale yellow, with sparse white hairs and with a single black bristle near the end; 
proboscis robust, vertical, nearly as long as the height of the head, black at base and apex. No humeral bristles, but the 
usual dorsocentral, scutellar and notopleural pairs present. Abdomen subshining, hypopygium small, not noticeably hairy, 
thelast ventral segment fringed. Legs dusky yellow, the hind femora, the upper side of the middle femora, the tips of all the 
tibiae and the end of the tarsi blackish, posterior tibize with a broad darker ring toward the base; front femora C white-ciliate 
beneath but not marked with black, front tibiae scarcely thickened, the inside closely setulose, middle femora loosely setulose 
within, and in the cj near the base with a strong mamillate tubercle bearing a pair of yellow spines, middle tibie closely 
setulose within, and in the cj flatly excised toward the end, the middle metatarsi of the c broadly flattened so as to be one- 
fifth as broad as long, and densely setulose on the edges.  Halteres entirely yellowish. ^ Outer two-thirds of the wings 
lightly infumated and with blackish veins, root of the fifth vein pale, third section of the costa about three times as long as 
the fourth section, the fourth vein bent forward near the tip, crossveins subequal, their separation less than their length, 
last section of the fifth vein three-fourths as long as the preceding section. 
Numerous specimens from Powell Co, Montana, July, collected by Wm. M. Mann : one specimen from Moscow, 
Idaho, taken by Dr. J. M. Aldrich. 
