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The Ohio Journal of Science [Vol. XX, No. 7, 



other species in having the hypopygium dark, with paler color only on 

 sides of venter. 



Orbit with five bristles; third antennal joint rounded at apex above, 

 cheek over one-fourth as high as eye, with one strong bristle and some 

 weak marginal hairs in addition to the vibrissa, the bristles pale; palpi 

 shorter and comparatively broader than in dissimilis. Presutural 

 acrostichals two-rowed, but with some weak, pale hairs between the 

 rows; disc of scutellum with very weak pale hairs. Fore femora swollen, 

 with a few weak, black, bristly hairs on apical half of anterodorsal 

 surface, and long soft hairs on postero ventral ; fore tibia with one antero- 

 dorsal bristle; mid and hind femora without ventral bristles, the former 

 with a few on apical half of anterodorsal surface, the hind pair with 

 an almost complete series on same surface; mid tibia with one antero- 

 and one posterodorsal bristle, the latter almost on the dorsal surface. 

 Third and fourth veins subparallel or slightly convergent apically; sixth 

 vein weak on apical half. Hypopygium of male very large; fifth sternite 

 with the apices of the lateral processes glossy, rounded, their inner 

 margins on basal half armed with very short, dense, erect hairs. 



Length, 5-5.5 mm. 



Type locality, Katmai, Alaska, July, 1917 (J. S. Hine). Six 

 specimens. 



Microprosopa triseta sp. n. 



Female. Similar in color to arctica. 



The head is slightly smaller than in arctica, the vibrissa and the 

 bristle below it are black, the palpi are slightly more elongate, with the 

 apices rather pointed. The presutural acrostichals are two-rowed, 

 without any pale hairs between. The mid tibia in type has only 

 one bristle on the anterodorsal surface, the hind tibia has in addition to 

 the bristles present in arctica one on the anterodorsal surface near 

 base. The venation is the same as in arctica, but the wing is more 

 pointed, so that the apex of third vein is very decidedly beyond apex of 

 fourth, while in arctica it is nearly in vertical line with it. 



Length, 4.5 mm. 



Type locality, Katmai, Alaska, July, 1917 (J. S. Hine). 



Microprosopa dissimilis sp. n. 



Female. Black; thorax densely yellowish gray pruinescent, almost 

 opaque; abdomen slightly pruinescent, shining. Head black, anterior 

 third of frons, the face and cheeks yellowish testaceous; antennae and 

 arista black, apex of second joint of former slightly pale; proboscis glossy 

 black; palpi whitish testaceous, faintly infuscated at apices. Thoracic 

 dorsum with two poorly defined narrow vittae anteriorly. Legs 

 yellowish testaceous; all coxa? fuscous. Short hairs on thorax and 

 abdomen black. 



Each orbit with six bristles, the anterior three hair-like; arista bare, 

 about one-third longer than antenna?, third joint of the latter slightly 



