544 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 56. 



PETROSARCOPHAGA ARIZONICA, new species. 



Length, 12 to 13 mm. Numerous specimens of both sexes, Sabino 

 Basin, Santa Catahna Mountains, Arizona, about 4,000 feet, Sep- 

 tember 18 to 30, 1918, on rock surfaces of canyon beds (C. H. T. 

 Townsend). 



Blackish, ashy- white poUinose. Apical portion of anal segment, 

 hypopygium of both sexes and palpi rufous. Head silvery-white, 

 frontalia and antennae blackish. Thoracic pollen whitish. Abdomen 

 tessellate with more ashy pollen. Legs blackish, tibiae more or less 

 brownish. Tegulae white. 



Type.~C&t. No. 22087, U.S.N.M. 



Tribe TEPHROMYIINI. 

 TEPHROMYIOPSIS, new genus. 



Genotype. — Megerlea rufocaudata Bigot, 1881.* 



Facial characters practically same as in Tephromyia. Epistoma 

 narrowed from clypeus. Arista long plumose. Apical cell short- 

 petiolate. Abdominal macrochaetae marginal. 



Tribe MILTOGKAMMINI. 

 OPSIDIOPSIS, new genus. 



Genotype. — Opsidioj)sis ohlata, new species. 



Differs from Opsidia as follows: Much narrower in form, sub- 

 equilateral viewed from above. Front not very prominent; face of 

 female narrower below than front. Frontalia in middle fully three 

 times as wide as one parafrontal. A proclinate-divaricate pair of 

 ocellars only. Parafacialia sparsely setose, little over half as wide 

 below as above. Cheeks of female about one-fifth eye length. Two 

 sternopleurals ; three postintraalars and postsuturals; one or two pre- 

 acrostichals and postacrostichals; a short discal pair of scutellars. 

 Last section of fifth vein over half preceding section. Abdomen 

 oblong; no median marginals on first segment, median marginal pair 

 on second and third, marginal row on anal ; the macrochaetae short. 



OPSIDIOPSIS OBLATA, new species. 



Length, 5.5 mm. One male. Wild Horse Canyon, Animas Moun- 

 tains, New Mexico, 5,000 feet, July 21, 1917, on tender mesquite 

 foliage (C. H. T. Townsend). 



Black. Head silvery, the pollen covering frontalia less thickly. 

 Palpi blackish, slightly rufous basally. Thorax and scutellum thinly 

 silvery; four thoracic vittae. Abdomen shining black, the foi'ward 

 half of last three segments silvery; the silvery fasciae becoming 



> Ann. Soc. Ent. France, ser. 6, vol. S, p. 269; Brauer, Sitz. Akad. Wiss., Math. Nat. CI., vol. 107, pp. 

 514-15. 



