52 c Canadian Arctic Expedition, 1913-18 



This species may be distinguished from any previously described from 

 North America by the hairy fore tarsi of the male and the presence of bristles 

 near base of mid femora in both sexes. 



PHORID^E. 



The larvae of the group in the present collection are found in fungi, manure, 

 or decaying vegetation. 



Aphiochaeta Brues. 



Aphiochaeta alaskensis, n. sp. 



Male. — Black, subopaque. Legs black, fore tibiae and tarsi, except tip, 

 brownish yellow, bases -of mid and hind tibiae brown. "Wings clear, veins dark. 

 Halteres black, knobs testaceous yellow. 



Post-antennal bristles four in number, the lower pair nearly as large as the 

 upper, lower frontal bristles in a nearly straight transverse line; antennae 

 above the normal size, third joint round, slightly less than half as large as eye; 

 palpi large, conspicuously setose; clypeus projecting, pointed; arista almost 

 bare, longer than width of frons; bristles on cheek long and strong. Dorsum 

 of thorax with rather dense setulose hairs; scutellum with two long apical 

 bristles and two weak lateral hairs; mesopleura with a number of weak, hair- 

 like bristles on upper posterior angle. Abdomen tapered to apex, with a few 

 bristles on apical segment; hypopygium rather large, with a long bristle on each 

 side near base, apical process large, oval. Legs slender; fore tarsi broad, hind 

 femora with short close fringe at base ventrally; hind tibia with a fringe of 

 six to seven short setulse on the apical three-fourths. Costa extending just 

 short of middle of wing, first division slightly longer than the other two combined, 

 third, half as long as second; costal fringe very long and widely spaced, the 

 bristles nearly twice as long as fork of third vein; fourth vein leaving just beyond 

 fork of third, gently curved at base, nearly straight for the remainder of its 

 length, slightly deflected at tip and ending slightly nearer to apex of wing than 

 does fifth. 



Female. — Similar to male. Differs in having the abdomen pointed at apex, 

 the antennae and palpi smaller, and the fore tarsi slender. 



Length, 2 mm. 



Type Localhvv: Nome, Alaska, August 24, 25, 1916 (F. Johansen). Eight 

 specimens. 



This species closely resembles vulgata Malloch, to which species it runs 

 in my key to North American species. 1 It differs, however, in the much darker 

 palpi, large antennae, and shorter costa, and in several other characters. 



Aphiochaeta platychira, n. sp. 



Male. — Similar in colour to the preceding species except that the halteres 

 are entirely black. 



Chaetotaxy of head as in alaskensis except that the lower post-antennal 

 bristles are very little more than half as large as the upper pair; antennae normal 

 in size: palpi not as strongly bristled as in alaskensis. Mesopleura bare; scutel- 

 lum with two long bristles. Abdomen narrow, apices of segments laterally with 

 a few long bristles, sixth with a number of bristles on posterior margin: hypo- 

 pygium small, with one to two short bristles on each side, anal process small. 

 Legs slender; fore tarsi broad, basal joint as broad as apex of tibia, and not 

 over twice as long as broad; hind tibia with very short setulose hairs on postero- 

 dorsal surface. Costa to very slightly short of middle of wing, first division 

 1-25 as long as next two together, third about two-thuds as long as second: 

 costal fringe very long, the bristles twice as long as fork of third vein; fourth 

 vein leaving beyond fork of third with a slight curve and running nearly straight 

 to margin of wing, ending distinctly nearer to apex of wing than does fifth. 



■ Proc. U. S. Nat. Mus., vol. 43, p. 452, 1912. 



