J. R. MALLOCH 159 



Type and allotype in collection of Boston Society of Natural 

 History, paratypes in collections of Illinois Natural History 

 Survey and of The American Entomological Society. 



Trichopticus diffinis ssp. n. 



Male. — Similar in color to spi/tiger, but the halteres are yellow. 



Differs from spinigcr in being smaller, and in having the mid femora with 

 a number of long hairs on basal half of postero-ventral surface. The mid 

 tarsus has the fringe of fine hair on postero-ventral margin of joints three to 

 five much weaker than in the two preceding species. The mid tibia in the type 

 has only one posterior bristle, the hind femur has from five to seven strong 

 bristles on apical half of antero-ventral surface. In other respects as in 

 spinif/cr, but the fourth joint of mid tarsus is shorter. Length, 4.25 mm. 



Type.—d'; Emigration Canyon, Utah, July 21, 1917, [Coll. 

 Aldrich]. 



Trichopticus melanderi sp. n. 



Male. — Similar in color to npiniger, differing only in having tiie knobs 

 of the halteres yellow. 



Eyes almost bare, scj^arated by about the width across posterior ocelli; 

 lower supraorbital bristle proclinate; face concave in profile, the mouth- 

 margin almost in line with ba.se of antennae; cheek over twice as high as 

 width of parafacial, the latter nearly as wide as third antennal joint; antennae 

 not as long as face, third joint nearly twice as long as second; longest hairs 

 on arista a little longer than its basal diameter. Presutural acrostichals 

 hair-like, irregularly four-rowed; postsutural dorso-centrals, three. Abdo- 

 men cylindrical, tapered; hypopygial forceps long, slightly knobbed at apices. 

 Fore tibia with hairs on posterior surface longer than elsewhere, and usually 

 with one weak posterior median bristle; fore tarsus distinctly longer than fore 

 tibia; mid femur normal, with slender bristles on postero-ventral surface; 

 mid tibia with one antero-ventral, one or two antero-dorsal, two or three 

 postero-dorsal, and one or two postero-ventral bristles; mid tarsus normal; 

 hind femur with a series of bristles from base to apex on antero-ventral sur- 

 face, and a much weaker series on apical half of postero-ventral surface; 

 hind tibia almost straight, with from four to six antero-ventral, two .or three 

 antero-doTsal, and four to six postero-dorsal bristles, the posterior surface 

 with a few long hairs on middle. Costal thorn small; apex of wing rounded. 



Female. — Less intensely black than male, but not so densely gray pruines- 

 cent as spiniger. 



Frons about one-third as wide as head; lower supraorbital not much longer 

 than second; interfrontalia without cruciate bristles. Fore and mid tibiae 

 as in male; hind femur with fewer bristles on antero-ventral surface and none 

 on postero-ventral; hind tibia as in male except that the postero-dorsal sur- 

 face has only one strong bristle and the posterior surface has no long hairs. 



Length, 4 to 4.5 mm. 



TK.-\XS. .Ul. EXT. SOC, XLVI. 



