322 DIPTERA 
Head narrow, the occiput conical; antennze whitish ; humeri 
pollinose; third and fourth veins parallel . . . . . . P. rERSUS, Coquillett. 
20. Thorax witlhia median broad blackish vitta . . . . i2... 5. V 45 sca rM ET 
Thorax withouta median vitta. .. . ... . . 4 3 X TNI d M 
21. Proboscis black; wings elongate, the posterior crossvein | 
beyond the anterior and oblique; tibial spurlarge . . . P.caricARIs, new name. 
Proboscis mostly yellow; posterior crossvein transverse . . . . . . . « . . « « a2. 
22. At least sides of thorax lightly pollinose; front densely pol- : 
linose; anal crossvein nearly perpendicular . . . . . ... . .. - - . . . 7. 33 
Thorax shining; front shining; middle femora with yellow 
sette beneath in addition to the biseriate setule; anal 
crossvein strongly recutved . .. . .-. 4" e Ii aai v a uice e M MEC 
23. Crossveins widely separated; middle femora setose as well 
assetulge . ... « . s... s. s. 4. 3 i. uw PRRUNDACFUE BOT. aD DE 
Crossveins meeting; middle femora not setose; northern | 
—— O0 eei AL UENE SIL 
24. Third antennal joint short ovate, yellow, one-third the arista; 
flexorsetze of middle femora strong ; crossveins at one-third 
length of wing; mesonotal hairs rather long and sparse; 
facesilvety . . . « . « «- 5. o 4 e PINNAE 
"Third antennal joint lanceolate, black. two-thirds the arista; 
flexor setze weak; crossveins at two-fifths length of wing ; 
hairs short and dense; face shining . . . . . . . . P. XANTHOCHITON, nov. sp. (2). 
(1) Platypalpus rubefactus, nov.sp. — Male. Length 1.75 mm. Body largely yellowish. Occiput black, 
hoary, its hairs long, sparse and white, sides of the concolorous front somewhat diverging above, epistome bare, 
proboscis yellowish, palpi rather large, white-pubescent; last antenal joint slightly infuscated apically, short-conical, 
one-half longer than broad and one-third as long as the thickened dark arista. Mesonotum dusted, a dark vitta 
occupying the central third, dorsal setule very sparse and seriately arranged in four rows, humeral bristle weak, 
two scutellars; pleurz pruinose, about half of sternopleura bare. Abdominal tergites brownish yellow, hypopygium : 
brown, terminal, larger than the diameter of the abdomen, its valves closely fringed with long curled yellow hairs. 
Legs entirely yellow, the apex of the tarsi infuscated, front femora with a half dozen outstanding hairs beneath, 
middle femora rather slender, with about twenty minute setula in each flexor row, in front and in back of which 
are outstanding yellow hairs, those in back fewer and much longer, spur of middle tibiae minute. Wings lutescent, 
three and a half times as long as wide, veins yellow, the third to fifth sections of the costa proportioned 6 : 3: 1, 
first posterior cell narrow, occupying one-fourth the width of the wing, its veins parallel, crossveins before the 
middle of the wing, the posterior transverse, spaced its own length from the anterior, anal crossvein at the middle 
of the basal cell, perpendicular, anal vein evanescent basally. 
Type : Chicago, Illinois, July, 1914 (Melander)  Paratypes, Plummer's Island, Maryland (McAtee). The 
female has the telescopic tip of the abdomen opaque yellow. 
(2) Platypalpus xanthochiton, nov. sp. — Female. Length 2.5 mm, Yellow, head black, mesonotum with 
a central brown vitta, tergites medially brown, legs entirely pale yellow, veins thin and blackish, crossveins meeting. 
Head globular, occiput dull, its upper hairs dense and pale, front moderately broad and shining, face and epistome shining ; 
proboscis yellow, palpi large and pale yellow; base of the antennze shining yellow, distal joint triangular, black, nearly 
twice as long as broad and about half the length of the finely pubescentarista. Disc of the mesonotum devoid of pollen but 
uniformly clothed with rather dense short fine whitish hairs, no humeral, two notopleural and the middle pair of scutellar 
bristles yellow. "The dark vitta is narrow in frontbecoming broader and diffusing posteriorly ; base of the scutellum brown, 
Abdominal hairs inconspicuous; terminal segments not ochraceous. Legs slender, front femora not ciliate, middle femora 
with twenty-five setulz in the anterior row and twenty in the posterior and with about ten weak yellow posterior setze, middle 
tibiz two-thirds as long as their femora, the spur small and yellow. Halteres, calypteres and root of wing pale yellow. 
Sections of the costa proportioned 10:7 : 5:2; of the fourth vein, 1 : 1.4, of the fifth vein, 2: 3: 4, third vein ending at 
extreme wing-tip, anal crossvein forming an angle of fifty degrees, anal vein faint, anal angle weak. 
Two specimens, Almota, Washington, June 2, 1918 (Melander). 
