ART. 17. XORTH AMERICAN PHOROCEEA ALDRICH AND WEBBER. 25 



front and face silvery, the sides of former sparsely haired; frontal 

 bristles reach the base of third antennal joint, the two uppermost 

 ones stout and reclinate ; face and front nearly of equal width, bucca 

 one-twelfth the eye height ; facial ridges bristly on the lowest fourth ; 

 palpi yellow, swollen at tip and sparsely haired ; antennae nearly as 

 long as face, the third joint two and one-fourth times the second; 

 arista tapering from base to apex, the penultimate joint short. 

 Thorax black, gray pollinose, marked with four black vittae and 

 bearing four dorsocentral macrochaetae. Scutellum black, gray polli- 

 nose, the tip yellowish, bearing three long and one shorter apical 

 pair of marginal bristles. Sternopleura with three bristles. Abdo- 

 men with discal and marginal bristles, the fourth segment, except- 

 ing the extreme base, with stout bristles all over ; first segment wholly 

 black, the remaining ones gray pollinose at base. Legs black; mid 

 tibiae bearing two bristles on the outside near the middle ; hind tibiae 

 ciliate, with two or three longer bristles. Wing venation as usual, 

 excepting that the last section of the fourth vein is strongly arcuate ; 

 third vein with two bristles at its base. 



Length 10 mm. 



Described from one female specimen collected at Great Falls, 

 Virginia. 



Ty^f'.— Female, Cat. No. 25706, U.S.N.M. 



A second female, collected at Lafayette, Indiana, September 14, 

 1917 (Aldrich), differs in only one character; it has no discal macro- 

 chaetae on the abdomen. The width of the front is the same. The 

 correspondence is so complete that we feel compelled to regard the 

 species as the same. 



ZENILLIA POLITA Coquillett. 



Exnrista poUta Coquillett, Revis. Tachin., 1897, p. 99. 



Abdomen black and shining; basal fourth of segments two and 

 three thinly gray pollinose at most; closely related to Zenillia set- 

 inervis. but does not have the third vein bristly to the small cross- 

 vein. 



Front in male 0.257 of the head width; face and front silvery 

 pruinose, the latter darker above, thickly clothed with fine bristly 

 hairs; three reclinate bristles on each side above; bucca one-eighth 

 the eye height ; facial ridges bristly on the lowest fourth ; antennae 

 as long as face, the third joint about five times the length of sec- 

 ond: arista slender, hardly thickened on the basal fourth; penulti- 

 mate joint short; palpi yellow. Thorax bearing four dorsocentral 

 macrochaetae, thinly whitish pollinose with four black vittae ; scutel- 

 lum bearing three long pairs of marginal and a shorter, cruciate 

 apical pair of bristles; sternopleura with three bristles. Abdomen 

 destitute of discal macrochaetae, black, shining, with a bluish tinge, 



