FAM. EMPIDIDZE 29 
rr. Recurved process of ventral pygidial valve broad, the dorsal 
valve duckbill-shaped; notal setule weak . . . . . . T. UNIVERSALIS, MELANDER. 
Recurved pygidial process narrow, dorsal valve with short 
narrow termination; notal setulee evident . . . . . . T.aAGcENs, MELANDER. 
12. Four pronounced scutellar bristles; abdomen bristly before 
pygidium; halteres black . . . . . . . . . . . T. TETRACHZTA, nOY. Sp. (1). 
PuteraPscutetlapBristes Toduced - 00. 3. 5 NOR EA eC. i diosa o ARCU o e eo oes 19: 
13. Halteres and palpi yellow; arista three times antennallength . . . . . . . . . . . 14. 
Halteres dull yellow to black; arista four times antennal 
lung EDEN REN (HN UEOE er IV Tu ago cues E PELA. Mi ee KO 
14. Third vein much stronger than fourth and clouded. . . . T. RuricomNis nov. sp. (2). 
"Third and fourth veins equal, infumation of wings uniform 
except forthe paler base. . . . . . . . . . . T. carva, MELANDER. 
15. WidpsliValae c o m o I NU Ne Duos. T. APICIS, Williston. 
Wings more or less infumated. . . . . eseQnN UM M aC trc e 
16. End process of pygidium leaf-shaped ; halteres vdiosddb hind 
femora yellow and brown; palpi white cf, blackish Q. .. T. EPiBOscA, nov. sp. (3). 
(1) Tachyempis tetrachaeta, nov. sp. — Male. Length 1.75 mm. Front broadly V-shaped, pollinose, two 
pairs of ocellar bristles, vertical bristles small, occiput completely coated with brown; basal antennal joint yellowish, apical 
black, arista relatively strong, twice the antennal length; palpi white, elongate ovoid, apical seta long and whitish. 
Notum dusted with brownish, bristles stronger than usual, humeri large, four notopleural, the center two strong, acrostichal 
and dorsocentral rows of setulze evident though small, the last two dorsocentrals setiform, four equal and strong scutellar 
bristles. Abdomen subshining, its hairs stronger than usual, the last segment bristly, pygidium large, the recurved termi- 
nal process rather broad.  Coxae and front legs yellowish, posterior legs yellowish brown, front femora robust, anterior 
femora with usual flexor setule.  Halteres and calypteres black. "Wings rather broad, with slight and uniform infumation, 
veins strong and blackish, costal sections proportioned about 1 : 0.6 : 0.6 : 0.3, first posterior cell ending at apex of wing, 
about five-sixths as wide as the submarginal at end of second vein, third and fourth veins apically parallel, distance between 
crossveins less than the length of the posterior crossvein, sections of fifth vein nearly 2 : 3. 
Holotype, Concepcion, Chile(R. Thaxter), deposited in the Museum of Comparative Zoology of Harvard University. 
(2) Tachyempis ruficornis, nov. sp. — Male. Length 1.9 mm. Body black, legs, antennz, mouthparts, hairs, 
bristles and halteres yellowish, wings lightly infumated along the veins.  Occiput shining, very lightly dusted, almost 
glabrous; front narrowly V-shaped, the ocelli rather large, ocellar bristles large. Antenne reddish-yellow, short, the two 
joints of equal size, the outer globular, with subdorsal arista, which is three times the length of the antenna.  Proboscis 
brownish, short and vertical; palpi short, narrow, tapering, white and with a long white terminal bristle. Mesonotum 
polished black, a little dusted anteriorly; one humeral, some supraalaar, a double row of about five acrostichal, and about 
seven dorsocentral bristles present, scutellum with four bristles, the inner pair long; pleurz finely scabrous so as to appear 
subshining : abdomen polished. Legs including the coxa testaceous, the outer half of the hind femora infuscated, the front 
femora strongest, setulae of middle femora long and fine. Halteres pale yellow, including the base. Wings narrow, slightly 
infumated except at the base, the darkening a little stronger along the third vein, the second section of the costa slightly 
longer than the third, curve of the second vein uniform, the marginal cell two-thirds as wide as the submarginal cell, third 
and fourth veins subparallel, the first posterior cell widest before its tip, anterior crossvein two-thirds as long as the posterior, 
the distance between the crossveins one-half greater than the length of the posterior crossvein, fifth vein not angulate at the 
posterior crossvein, its sections subequal. 
One specimen collected by Dr. P. P. Calvert, March 4, 1910, at Cachi, Costa Rica, at 3450 ft altitude. 
(3) Tachyempis epibosca, nov. sp. — Male. Length r,75-2 mm. Occiput lightly dusted, lowerorbits polished, 
front very broad above, vertical bristles smaller than the ocellar pair, sometimes minute, ocelli moderately large; antennae 
brownish, arista thin and four times the antennal length or even longer; palpi narrow, white, with three small apical white 
setze, proboscis black. "Thorax completely dusted with brownish, pleurz not becoming cinereous on lower part, the single 
notopleural and scutellar bristles black, the supra-alar setulze brown, seriate setulae of notum developed though small, poste- 
rior dorsocentral not developed, no humeral. Abdomen dull piceous, pygidium large, elongate, very complex when open. 
the recurved terminal process ending in a broad leaf-like expansion, no specialized sete.  Coxae and legs pale yellow, the 
front tibize and apical half of hind femora brownish, legs elongate, front femora setose below, middle femora with a row of 
short setae below, the basal seta long and yellow, middle trochanters with two or three small black spinules. Halteres sordid 
yellow, the root yellowish, calypteres and fringe dark. Wings elongate, somewhat infumated over basal half of third vein, 
veins brown, sections of costa proportioned 1 : 1.3 : 1.6 : o.5, fourth vein ending beyond wing-tip, sections of fifth vein 3 : 4. 
Female, palpi blackish, 
Three males and five females, La Suiza de Turrialba, Costa Rica (P. Schild). 
