DIE OMPHR ALID EN . 
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1. Pseudatrichia griseola Coquill. 
& Ç. «Head yellow, opaque, gray, pruinose; upper part of the 
occiput and the antennae black ; proboscis and palpi yellow ; thorax 
black, opaque, densely gray pruinose, the humeri and spots on the 
pleurae yellow; scutellum yellow, marked with a median brown vitta; 
abdomen yellowish, subopaque ; knobs of halteres and the legs yello¬ 
wish ; wings hyaline ; veins yellow ; last section of third vein less than 
half as long as the preceding section. Length 3—4 mm. Mesilla, North 
Mexico, 25. Y. Los Angeles Co. Calif. A pair from the latter locality, 
captured by the writer, were resting on the bare ground like a Thereva 
2d*l $. 
Type: No 4712. U. St. Nat. Mus.» 
2. Pseudatrichia flaviceps Coquill. 
9 : «Head dark yellow, the occiput except the sides and an 
emargination behind the ocelli, an ocellar spot, and a spot in middle 
of lower half of front black; antennae and mouthparts black; thorax 
and scutellum polished black, a large yellow spot at inner side of each 
humerus, an interrupted white line below each wing, hairs of mesono- 
tum short, depressed, brassy yellow, arranged in stripes, those of 
pleurae white ; abdomen polished, bronze black, hind margins of seg¬ 
ments 2—6 white ; legs black, knees yellow, this color most extended 
on the front pair; wings hyaline, veins brown, apex of second vein 
close to tip of first; halteres pale brown, marked with a few white 
streaks and dots. Length: 6 mm.» 
Williams, Arizona. 2 ç July 15. 
Type: No 6193. U. St. Nat. Mus. 
3. Pseudatrichia pilosa Coquill. 
cT : «Black, polished, dorsum of abdomen bronze colored hind 
margins of segments 2—5 white, halteres white, a blackish spot on 
upper side of each knob ; thorax and femora covered with rather long 
nearly erect white hairs mixed with many black ones on the mesono- 
tum, wings hyaline, veins brown, second vein ending close to apex of 
first. Length : 4 mm 2 d . » 
Williams, Arizona. July 7. Hot Springs, Arizona June 28. 
Type: No 6194. U. St. Nat. Mus. 
4. Pseudatrichia unicolor Coquill. 
c? : «Black, apices of knobs of halteres white, legs yellow, apices 
of tarsi, of hind femora and both ends of hind tibiae brownish ; front 
polished ; mesonotum opaque, with rather coarse reticulations ; abdomen 
opaque, the 1., 5. and following segments polished; wings hyaline; 
veins brown, last two sections of third vein subequal in length ; costal 
12 
Annales Musei Nationalis Hung arici. XI. 
