3o6 Professor Aldrich on the 



Sympycnus. 

 Loew^ Neue Beitr., v., 1857. 



1. Sympycnus falco, n. sp. 



^ . Face blackisli, the eyes nearly or quite contiguous about 

 the middle ; front blackish ; antennge black, third joint short, 

 pointed, with a subapical arista. Cilia of inferior orbit pale. Dor- 

 sum, of thorax green, but little shining ; pleurae black with 

 greenish-grey dust ; halteres yellow ; cilia of tegulse black, still 

 rather brown at tips, and the lower two or three hairs yellow. 

 Abdomen dull green, with blackish hairs ; on each side of 'the 

 first segment is a row of half-a-dozen long brownish hairs ; the 

 hypopygium projects in a sort of rounded knob behind the 

 abdomen, its short, stout, brown grasping organs mostly concealed, 

 and lyiug in front of the organ proper. CoxaB varying from 

 yellow to brown in different specimens, the middle ones darker 

 than the others, the front ones with yellow hairs and a few slender 

 brownish bristles ; femora, tibi^ and tarsi yellow ; the fore 

 femora have a short row of brown bristles on the hind side near 

 the tip, the fore tibiae on the front side with only delicate irregular 

 hairs, in part rather long ; the fore tarsi are longer than the tibise, 

 the last joint rather long with a projection on the under side near 

 the base ; the inner claw folds back to meet this, thus forming a 

 clasping organ ; all the tarsi are only gradually infuscated near the 

 tip. Wings slightly yellow, slender, the posterior cross- vein before 

 the middle ; from the cross-vein, the second and fourth veins are 

 parallel, while the third converges toward the fourth in the latter 

 part of its course. 



$ . Face moderately narrow, black, with white pollen ; fore 

 femora and tarsi plain ; venter brownish near the base ; lateral 

 bristles of first abdominal segment shorter. 



Length l'6-2 mm. ; of wing, the same. 



Four males, six females. 1000-3000 feet altitude. 



2. Sympycnus similis, n. sp. 



^ . Differs from the foregoing species chiefly in having on the 

 front side of the fore tibiae a row of four very stiff, stubby bristles 

 of moderate length. The coxae and wings are also a little darker, 

 and the hypopygium projects a little more behind. Length 

 rO mm. ; of wing, 1'7 mm. 



One male. 1000 feet altitude. 



