AUT. 25. XEV\^ SPECIES OF THE GENUS DOLICHOPUS ALDBICH. 9 



gradually becoming black at the apex ; the extreme tip, however, is 

 yellow. Front and middle tibiae pale yellow ; the hind tibiae black 

 with a brown streak on the posterior except near tip ; they are consid- 

 erably longer than their femora and their tarsi are strikingly elon- 

 gated and enlarged, and deep black in color; the second joint of tha 

 hind tarsus seems especially enlarged and noticeably flattened; the 

 following joints of similar appearance but decreasing in size ; front 

 and middle tarsi plain, infuscated from the tip of the first joint. 



Wings hyaline with a perceptible brown tinge on the anterior half 

 except at base ; costa not thickened ; anal angle very much reduced. 



/^emaZe.— Face a little wider than in the male, rather gray in color. 

 Antennae longer than usual in the female, the third joint with an 

 uncommonly sharp tip but very much shorter than in the male. Cilia 

 of the calypters sometimes in part black. Femora colored as in the 

 male ; the hind tibiae, however, yellow except on the apical fourth ; 

 they are longer than the femora as in the male and the hind tarsi are 

 considerably elongated and entirely black but the joints are not en- 

 larged or flattened. The wing has a distinct brownish tinge which is 

 not confined to the anterior half. 



Length 3.1 mm. 



Described from 12 males and 13 females collected at Fairbanks, 

 Alaska, on June 30, 1921, by the writer. 



Type.— Male, Cat. No. 25189, U.S.N.M. 



The striking enlargement and black coloration of the hind legs 

 suggested the name, the idea being than these characters are probably 

 displayed while hovering in the air, the legs hanging down. 



In the tables of Bulletin 116 I would put this in Group F, in spite 

 of some infuscation of the front femora ; it would then run to acutus, 

 page 15, but the latter has no infuscation of any of the femora, etc. 



DOLICHOPUS SIMPLICIPES. 



new species. 



Male.— Front rather dull green. Face narrow, silvery, with a 

 slight yellowish tinge. Palpi yellow. Antennae black,*^ the first 

 joint faintly yellowish below on the inner side, the third joint rather 

 broad, but not elongated. Orbital cilia white except a few above. 



Mesonotum and scutellum bronze-green, not very shining. Pleurae 

 greenish-black, with a rather thick gray dust. Calypters with black 

 cilia. Halteres yellow. Abdomen shining green, not very bright, 

 a thin whitish pruinosity along the sides. Hypopygium black, of 

 moderate size, the lamellae oval, white, with a narrow margin above 

 and a broader one at apex, where there are the usual notches and 

 curved bristles. 



Front coxae yellow, with a small indistinct dark spot at base on 

 the outer side; the front side with pale hairs; middle and hind coxae 

 black except at tip. Femora yellow; the hind ones slightly infus- 



