AMERICAN DIPTERA. 253 



the same tendency to vary in the coloring of the wing as do 

 the Atlantic specimens." I have seen the above-mentioned 

 specimens and lay particular stress upon the variations in the 

 coloration of the wings in the male, as I believe that Dr. Wil- 

 liston's sackeni, with more extended collecting, will prove to 

 be but a male variety of albius. Prof. C. W. Johnson has a 

 typical sackeni, except that the mystax, pile of front, occiput, 

 and antenna is pale golden instead of white, taken at North 

 Mt., Pa. 



Dioctria nitida. 



Dioctria nitida Williston, Trans. Am. Ent. Soc, XI, 8, 1884. 



(^ 9- — Length 11-13 mm. — Polished black, wonderfully Uke albius, 

 but larger, and all the tibiae, except their tips, bright reddish-yellow. 



Face densely, front more thinly, brassy-yellow; occiput grayish 

 pruinose, especially along the orbits. Proboscis, palpi and antennae, 

 black, the last in structure similar to those of albius; pile of mystax, 

 basal segments of antennae, frontal orbits, ocellar tubercle and upper 

 occiput black; pile of lower occiput and proboscis white. Thoracic 

 dorsum with very short fine golden pubescence denser on the sides 

 than elsewhere, but with golden, not black, bristles, which are more 

 numerous above the insertion of the wings than in albius; pleurae 

 polished, with four light golden spots arranged as in albius; trichostical 

 pile pale yellow; scutellum bare, polished. Halteres yellowish- white. 

 Abdomen polished, black, with coppery reflections; pile sparse, golden, 

 microscopic; longer on sides of segments 1 and 2. Legs black; coxae 

 white pruinose, with white pile as in albius; femora with pale pile, 

 thicker below; front and middle tibiae, except their tips and the hind 

 tibiae, more broadly, reddish-yellow, with bristles of same color; claws 

 black; pulvilli tawny. Wings nearly uniformly blackish, veins yel- 

 lowish at base; in some specimens the veins are wholly yellow in basal 

 half; all the posterior and the anal cell open. 



Type. — -University of Kansas. Four male and one female 

 specimens. 



Habitat. — -Washington (type) ; Seattle, Wash, (May 1) ; Cali- 

 fornia (Hy. Edwards) ; San Gabriel, Los Angeles Co., Cal. 

 (June) . 



Dioctria parvula. 



Dioctria parvulus Coquillett, Can. Ent., XXV, 80, 1893. 

 c^. — Length 4 myn. — Wholly polished black; base of wings a? far as 

 the fifth posterior cell yellowish-white, beyond this blackish. All the 

 posterior and anal cells open. Pile of head light yellow, that on sides 



TRANS. AM. ENT. SCO., XXXV. JULY, 1909. 



