418 ENTOMOLOGICAL NEWS. [Nov., '17 



Legs black with white pile; knees, base of tibiae, two basal joints of 

 anterior four tarsi reddish-yellow or reddish-brown: pile on inferior 

 surface of tarsi and tibiae golden yellow; hind metatarsi slightly 

 thickened. 



Abdomen wholly shining black with white pile, more abundant on 

 sides than on disc; abdomen oval, equal in length to head and thorax 

 combined; maximum width slightly exceeding that of thorax. 



<3 . Body narrower than in female, general character similar. Head : 

 Vertical triangle shining black with more or less black pile in region 

 of ocelli; frontal triangle shining black, on sides with black pile, in 

 center and above with light-colored pile (some specimens have the pile 

 all black except for a few hairs just above antennae). Eyes contigu- 

 ous for about 10 facets. 



Antennae : Length somewhat variable, in general shorter than in 

 female, shape of third joint more orbicular, coloration similar. 



Thorax black shining, clothed with light yellow pile, which is longer 

 than in the female. 



Legs colored as in female, in some specimens the apical and basal 

 fourth of tibiae and the first three tarsal joints of anterior four legs 

 are yellow. 



Abdomen with broad, ill-defined dull black bands at the bases of 

 segments, elsewhere shining metallic; pile light yellow and white, 

 abundant along the sides and much longer than in the female. 



Described from 6 females and 14 males. 



Type 9 and allotype $ in the collection of the U. S. Na- 

 tional Museum. 



Type locality, Walnut Creek, Calif. 



A common valley species appearing towards the end of 

 March. The adults have been taken until October, but are not 

 abundant after May. In 1913 they were very abundant in 

 spring, flying about wild rose bushes (Rosa} and since then 

 they have been observed frequently in April about blossoms 

 of poison oak (Rhits divcrsiloba T. & Gr.), in May about 

 grape flowers, and throughout summer about aphid infesta- 

 tions on trees such as Black Walnut (Jnglans californica Wat- 

 son). The larvae is aphidophagous, a male fly having been 

 reared in May, 1914, from a larva found feeding upon the 

 sexes of Pemphigus populicaulis Fitch (Aphid.) underneath 

 detritus about poplar bark. 



The author had previously considered this species P. pis- 

 tic aides Will., and has twice referred it to that species (Jour- 



