524 PliOCEEDJXGS OF THE XATIOXAL MUSEUM. vol. 44. 



lighter yellow, segments with numerous long black hairs. Front, 

 vertex and occiput dull yellow with a brown tinge; gense clearer 

 brown. 



Thorax: ])ronutum light yellow. Mesonotum: prsescutum covered 

 with a thick pubescence, light yellow with two brown stripes on either 

 side of the median hue, these stripes pale, yellowish-brown in front ; 

 a large rounded brown spot on the sides of the sclerite before the 

 pseudosuture ; scutum, scutellum and post-notiun brown, the latter 

 darker. Pleurse light yellow with a broad brown band running from 

 the side of the pronotum, backward under the wing-bases to the post- 

 notum; sternum light browTi. Halteres broken, stem j^ellow. Legs 

 light yellow, a light brown ring at the tip of the femora, a darker one 

 at the tip of the tibiae; tai-si, tip of segment 2, all of 3 to 5 dark brown; 

 legs denseh' hairy. 



Wings: hyaline with two brown bands, one traversing the wing- 

 basis, extending from near the humeral cross vein to the origin of the 

 sector, narrower in the anal cells. The second band is in the vicinity 

 of the cord, cells second Rj almost all included, base of cell R3, tip of 

 cell R, base of cells R^ and first M,; a prominent brown cloud at the 

 basal deflection of Cuj and along the second deflection of M3 and cross 

 vein m (outer end of cell first M2) ; a very pale brown cloud extends 

 across the cells R,, R3, R-, and M,. Venation (see fig. 30). 



Abdomen: tergum light yellow; all except segment 5 mth the 

 sclerite largely browTi, especially caudally and laterally; segment 5 

 clear yellow; sternum light yellow. 



Ilolotype. — Female, Rio de Janiero, Brazil (November) (coll. H. II. 

 Smith). 



Type. — In American Museimi of Natural History. 



Genus TRIMICRA Osten Sacken. 



Tnmirra Osten Sacken, Proc. Acad. N.<it. Sci. Phila., 1861, p. 290; Monooraphe, 



vol. 4, 1SG9, p. 165; Studies, etc., pt. 2, 1887, p. 195. 

 Ilhia HoKu.-vNi, Prodr., vol. 1, 1856, p. 182. 



KKY TO THF, AMERICAN SPECIES OF TRIMICRA. 



1. Antenna^ uniformly brown; wings not pubescent; large species, length, 7 mm. or 



over anomala Osten Sacken.' 



Antennae with the basal segments yellow; wings pubescent; small species, length, 

 5 mm. or less pygmsea Alexander.' 



In the United vStates National ^hiseimi collection is a series of 

 sp(>cimens from Mexico which agree very well with the description of 

 T. anomala, and I have determined them as such. As to whether or 

 nc>t this sj^ecies is conspecific with the European Trimicra pilipes 

 Fabricius, as given bj' Osten Sacken in his Western Diptera, page 200, 



> Proc. .Vcad. Nat. Sci. I'hila., 1S61, p. 290; MonoRraplis, vol. 4, p. 167. 



> Psyche, vol. 19, Deo., 1912. p. IWi, pi. 13, fig. :i. 



