NO. 2115. NEW NEOTROPICAL MU8C01I) FLIES— T0WN8END. 427 



whole length, third vein bristly to or even beyond small crossvoin. 

 Apical cell ending about as far before wing tip as length of second 

 anteimal joint, open. Fourth vein rounded, only gently bent in 

 after cubitus. Hind crossvein much nearer cubitus. A hairhko 

 pair of ocellar bristles. 



EXORISTOPSIS SETIFERA, new species. 



Length of body, 7 mm.; of wing, 5 mm. One female, Chosica, 

 Peini, about 2,800 feet. May 9, 1913, on flowers of Milcania, sp. 

 (Townsend). 



Black, ashy pollinose, upper parts with pale golden tinge. Face 

 rather silvery polUnose, paraf rentals light golden pollinose. Front- 

 aha dark brown. Antemiae blackish, the articulation of second and 

 third joints rufous. Palpi rufous, blackish on base. Thorax show- 

 mg four vittae, the outer ones slightly heavier than the imier. Tip 

 of scutellum paler. Whole upper surface very pale golden poUinose, 

 the golden tinge increasing toward tip of abdomen; leaving only the 

 thoracic vittae, first abdominal segment and lateral incisures of 

 abdomen blackish, the tip of abdomen light rufous under the pollen. 

 Legs black. Wings clear. Tegulae nearly white, the hind scale 

 rather watery. 



Holotype.— Cat. No. 19446, U.S.N.M. TD 4150. 



ZYGOFRONTINA, new genus. 



Genotype. — Zygofrontina capitis, new species. 



Difl;ers from description of Azygobotliria only as follows: Female 

 only. Front at vertex considerably wider than eye, at antennae 

 nearly one and one-half times eye-width. Face below four-sevenths 

 of head-width. Facialia strongly cihate nearly or quite liaKway up, 

 but short of the lowest frontals; latter descending below aristal 

 insertion. Eyes very large, cheeks not over one-fifth eye-height. 

 Third antennal joint about four and one-half to five times as long 

 as second. Arista thickened on basal two-thirds, hardly as long as 

 third antemial joint, basal joints each as long as wide. The weak 

 apical pair of soutoUar bristles is suberect, curved upward. Median 

 marginal macrochaetae of second abdominal segment vestigial, barely 

 differentiated from the short bristly hairs. Claws not as long as 

 last tarsal joint, front tarsi not widened. Hind tibiae weakly cihate. 

 Fourth vein angular at bond. Eyes thinly set with very short and 

 almost imperceptible hairs. 



ZYGOFRONTINA CAPITIS, new species. 



Length of body, 7 mm. ; of wing, 5 mm. One female, San Rafael, 

 Casma, Peru, on flowers of Asclepias curassavica, April 3, 1912 

 (Townsend). 



