340 à DIPTERA 
Third antennal joint much shorter than the rather stout arista; 
middle femora dark, and unarmed on anterior surface. . P. PriLaTUS, nov. sp. (1). 
9r. Epistome silvery white pruinose; third antennal joint three- : 
fourths as longaasthe arista; tarsi strongly annulate; sections 
of the fifth vein proportioned 0.5: 0.8: 1. . . . . . P. xquaus, Loew. 
Epistome shining black; antennz shorter end arista longer; 
tarsi not strongly annulate. . . . : E M quU uL uM 
92. Palpi yellow ; base of the antennz yellow, the third joint with 
astraight upper edge . . . ; . adde Daci. uua s MC MCN UR d HN 
Palpi blackish inside; antenns black, the third joint ded 
last section of the fifth vein dcus to or — than the 
preeding . . . . - . P.svurom, Melander. 
93. Basal cells aries TEES sections ot the fifth vein pro- ; : 
portioned o.8 : 1.5 : 1, first posterior cell ending beyond 
the tip of the wing ; pollen of the mesonotum golden . . P. CREPIDARIUS, nov. Sp. (a). 
in four equidistant rows, the usual bristles all present, strong and black, humeral strong; sternopleurz polished. 
Sides of the first abdominal segment lightly pollinose, remainder of the abdomen shining except the dull apex, hairs 
very short, pale and sparse. Posterior coxz black, legs very robust, front femora with spinous black bristles near the 
knee, the pair on the front face pronounced, middle femora armed with six black spinous thorns in a flexor row before 
the setulae and with about five more slender black outstanding bristles forming a longitudinal row down the middleof 
the anterior face, twenty-one setulze in the anterior flexor row and seventeen stout setze in the posterior row, tibial spur 
as long as the diameter of the tibiz, tipped with black, all the tarsi weakly annulate. Calypteres and root of halteres 
brownish, fringe and knob of halteres yellow. — Wings hyaline, two and a half times as long as broad, the anal angle — — 
full, veins thin and blackish, sections of the costa proportioned 5: 3:2: 1, first posterior cell ending at the wing-tip, — — 
its veins straight and parallel, crossveins at three-sevenths the wing-length, the posterior before the anterior and nearly — 
transverse, outer sections of fifth vein proportioned 2 : 3, anal crossvein straight, lung, forming an angle of forty-fve — 
degrees, anal vein uniformly weak. 
- One specimen of this distinct species from the southern end of Lake McDonald, Glacier National Fetk, Montana, 
August 14, 1916 (Melander). 
(1) Platypalopus pilatus, nov. sp. — Female. Length 2.2 mm. Black, pollinose, bestias basi gs vellosMd 
posterior coxae blackish, tibial spur strong, crossveins meeting before the middle of the wing. Head globular, 
front and face short and of moderate breadth, epistome shining black; palpi blackish, spatulate, the anterior surbice 
yellowish pollinose and with a few setze; antennae short, three-jointed, 'the third joint pyriform, one-half longer than 
wide and two-thirds as long as the rather thick arista; two pairs each of ocellar and vertical bristles. Pollen of the 
dorsum moderately dense, of a yellowish gray color, two humeral bristles and one pair each of notopleural, supraalar, 
postalar, dorsocentral and scutellar bristles: pleurz cinereous pollinose, the sternopleure largely glabrous; abdomen 
shining, the pits prominent. Front femora with yellow flexor cilia, middle femora stout, brown, with a few yellow 
set in front and a series of longer ones behind, middle tibizg* two thirds as long as their femora, tarsi not annulate. 
Veins firm, first vein slightly thickened on entering the costa, the second, third and fourth sections of the costa 
proportioned 4.5: 2.5 : 1, third and fourth veins nearly straight and parallel, crossveins meeting at two-fifths the length 
of the wing, nearly transverse, the posterior three times as long as the anterior, sections of the fifth vein proportioned 
4 : 0.6 : tr, marginal cilia short. 
One specimen, collected at Friday Harbor, Washington, July 4, 1905, by Dr. J. M. Aldrich. 
(2) Platypalpus crepidarius, nov. var. — Female. Length 2 mm. Black, dorsum moderately covered 
with yellow-gray pollen, legs and bristles black. ^ Occiput densely cinereous pollinose, one pair each of ocellar 
and vertical bristles ; front cinereous, its sides parallel, face white pruinose, epistome shining black; palpi oval, 
yellow, with white apical setze, proboscis black ; antenna three-jointed, the basal joints yellow, the third joint 
conical, about one-third as long as the thickened arísta.  Humeral bristle small, one pair each of notopleural, 
supraalar, small postalar, dorsocentral and scutellar bristles; pollen of the pleurz  denser and white, the glabrous 
spot occupying one-half of the sternopleurz; abdomen shining black. Legs including the coxe yellow, tarsi a 
little dusky towards the apex, front femora ciliate beneath, middle femora ciliate in front and setose behind, tibial 
spur strong. Veins yellowish, costa not swollen, its second, third and fourth sections proportioned 5 : 3 : 1, third 
vein ending at the tip of the wing, crossveins almost meeting, the posterior but little oblique, sections of the fifth 
vein proportioned 0,8 : 1,5 : 1, anal crossvein forming an angle of fifty-five degrees, anal vein uniformly faint, 
marginal cilia shorter than the anterior crossvein. 
One specimen, Woodland, Washington, May 23, 191o (Melander). 
