TAXONOMY OF MUSCOIDEAN FLIES — TOWNSEND 1 33 



tion clear. Abdomen in both sexes wholly opaque, brown or black 

 in ground color, more or less golden pollinose, never with translu- 

 cent portions. Scutellum always yellow. Both sexes have yellow 

 on the wings. Hind femora not at all ciliate. Tegulse white or 

 yellowish. Parasitic in Acridiidae (Dissosteira), so far as known. 



The male has frontalia suddenly narrowed, presenting a curved 

 outline on each side, closely followed by the frontal row of bristles, 

 the width on posterior half being only one-half the width at base of 

 antennre. Claws strongly elongate in male, hypopygium exserted 

 and tucked up under the end of abdomen. 



The female has the frontalia but little narrowed behind, being 

 evenly narrowed from anterior to posterior end, the sides and frontal 

 row of bristles being quite straight. Claws somewhat elongate in 

 female, even slightly longer than last tarsal joint, but very markedly 

 less elongate than in male. Anal end of abdomen truncate, the ovi- 

 positor more or less withdrawn within anal segments, its apex 

 usually showing. 



Type, T. trifasciata H. Loew. 



The other species belonging here are histrio Walker, indivisa 

 Townsend, probably umbra Walker and plumipes J. C. Fabricius ; 

 also the following new species. The writer formerly suggested 

 these (except plumipes) as varieties of one species, but now con- 

 siders them valid forms differing in marked characters. They form 

 a group apart by themselves, distinctly contrasted with the other 

 members of the Trichopodini. 



Polistomyia subdivisa, sp. nov. 



One female, St. Helena, Napa County, Cal., bred by A. Koebele 

 from a locust (Dissosteira venusta Stal) ; issued August 30, 1887. 



Length, 6.33 mm. Segments three and four of abdomen golden 

 pollinose, segment three with a median vitta and median hind mar- 

 gin brown, segment four wholly pollinose with a trace of vitta, seg- 

 ment two with a large yellow spot on each side, and segment one 

 with a similar smaller spot on each side. 



Type.— Cat. No. 10,881, U. S. N. M. 



Two female specimens from Las Cruces. New Mexico, collected by 

 the writer, August 25 and September 2, on flowers of Solidago ari- 

 zonica, are larger, measuring 7 to 8 mm., show no median vitta on 

 third and fourth segments, and only a faint vitta on second segment, 

 which bears a fascia rather than separated spots. They very likely 

 represent another form, but more material is needed from California 

 and New Mexico before separating them as distinct. They occupy 

 an intermediate position between trifasciata and subdivisa. 



