212 U.S. NATIONAL MUSEUM BULLETIN 2 77 



veins tan; halter stem brown, knobs cream, with a marginal brown 

 band. Legs: femora red-brown, pollinose; tibiae tan; tarsi tan, dark- 

 ening to brown distally. 



Abdomen second segment with a red-brown "T," with a broad 

 lateral base, remainder and posterior portion of segment white, 

 remaining segments with red-brown "T"s then fading out to all 

 white; ninth tergum white, with brown basal patch, hairs very long; 

 see figure for details. 



Female. — Head cream; eyes red-brown, probably metallic in life; 

 postocular rim broad, with thin brown patch behind eyes; frons 

 broad, with a tan "Y"-shaped band extending from antennae to 

 ©cellar triangle and the width of the latter; ©cellar tubercle red-brown, 

 pollinose; ocelli red; a groove extending from corner of eye to lateral 

 ocelli and then nearly straight to back of head, cutting off a portion 

 nearly as wide as ocellar tubercle separating the two postocular ridges. 

 Antennae with first segment brown, second tan, third orange, dark- 

 ening at the tips; see figure for details. 



Thorax dorsum with red-brown central and two lateral bands 

 separated by an orange stripe running between orange area above 

 humeral callus to central area on posterior third of dorsum, lateral 

 margins orange; all dusted with gray pollen; humeral and supra- 

 alar calli cream; scutellum yellow, with a narrow median band of 

 red-brown, pollinose. Prothorax cream, mesanepisternum cream with 

 red-brown patch, mesokatepisternum red-brown with a dorsal yellow 

 stripe, all pollinose. Wings smoky, veins brown; halter stem tan, 

 knob cream with tan marginal stripe. Legs with femora brown, 

 pollinose; tibiae tan, tarsi tan, darkening to brown distally. 



Abdomen second segment with a brown "T" with a red-brown 

 central stem and broad base in a field of yellows-brown, red-brown 

 "T" on third and fourth segments, turning to yellow-brown beyond; 

 eighth segment yellow-brown, shining; ninth tergum with 6 spinelike 

 hairs, somewhat hairy. See figure for details. 



Length: Male body 3 mm., wing 2 mm.; female body 4.5 mm., 

 wing 2.2 mm. 



Type-locality: Riverside, California; 19 September 1950 (Timber- 

 lake). 



Holotype: Male (CAS) 8921 (ex [PHT]). 



Allotype: Female, same data. 



145. Brevitrichia yucatani, new species 



Figure 139 



Brevitrichia griseola D. E. Hardy (not Coquillett), 1944a, p. 34. 



Male. — Head tan; eyes red-brown, with a metallic glint above, 

 black-brown below; frons small; ocellar tubercle black-brown, ocelli 



