AMERICAN BIPTERA. 83 



Macellocerus Mik. 



Mik, Dii)terologische Untersncbungen, p. 3, 1878. 



31 ALES. 



1. Antennal arista with a lamella in the middle as well as at the tip. 



bino<latiiisi Loew. 

 Antennal arista with an apical lamella only 2. 



2. Anterior femora thickened, black below on the basal half- . .olympise n. sp. 

 Anterior femora not thickened, yellow 3. 



3. Outer side of fore femora with long, curly hair aural us n. sp. 



Outer side of fore femora with plain hair 4. 



4. Anterior tibiae with a row of erect, flattened bristles on the outside below. 



sanus O. S. 

 Anterior tibiae with only a few common bristles on this part- -Uioecliu^i Loew. 



FEMALES. 



1. Hind femora yellow, two preapical bristles auratus. 



Hind femora largely black, one preapical bristle 2. 



2. Front tibiae wholly yellow mceclius. 



Front tibife largely black 3. 



3. Four anterior femora green-black, the apical third yellow, distinctly limited. 



sanus. 

 Four anterior femora largely yellow, the brown at base not distinctly limited. 



olympise. 

 (The female of blnodatus is unkuowu) 



9Iacellocerus olyinpise n. sp. 



Male. — Face long, bright yellow, slender in the middle ; antennae yellow, the 

 third joint blackened except at base, second joint rudimentary ; arista one and a 

 third times as long as the vertical diameter of the head, white except the incras- 

 sated base and the obovate black lamella, which is a little smaller than the third 

 joint; lateral and inferior orbital cilia light yellow. Thorax and abdomen 

 bronze-green ; tegulae yellow, with black cilia; fore coxae yellow, bare except the 

 tip. Fore femora iucrassated at the base, with a peculiar circular black spot seem- 

 ingly stamped upon the outer side, reaching beyond the middle; the inner side 

 is yellow, with a delicate pruinosity ; fore tibiae yellow, with numerous and rather 

 long bristles ; fore tarsi a little compressed, short, black ; posterior femora and 

 tibiae yellow, tips of the latter narrowly blackened, tarsi black ; bristles of the 

 tibiae rather long. Hypopygium large, basal part shining black, central segment 

 bronze-green behind, lamellae whitish, covered with black hairs, those of the 

 margin hardly coarser. Wings exceedingly slender, grayish, lighter at the root. 



Female. — All the body color darker, face wider and greenish yellow, third joint 

 of the antennae black, all the coxae black, femora more or less dark on the basal 

 part, the hind ones wholly black-green except the apical third ; tibiae black on 

 the apical third or fourth. Wings longer and much wider than in the male. 

 Length 6 mm. ; of wing 4.2 mm. 



Two males, two females, Olympia, Wash. (Trevor Kincaid), Jime 

 3 and July 1. 

 Iflacellocerus auratus n. sp. 



Male. — Face long, golden-yellow, very narrow in the middle, antennae bright 

 yellow, small, the second and third joints both very minute and rudimentary, 

 arista black, one and a half times the length of vertical diameter of the eye, the 



TRANS. AM. ExVT. SOC. XXIII. M.ARCH, 1896. 



