10 PROCEEDINGS OF THE NATIONAL MUSEUM vol.74 



The species has some resemblance to P. trivittata Townsend, de- 

 scribed from Peru,^ but the general color of the thorax and abdomen 

 is much blacker and the pollen is rather bluish instead of yellow 

 so that the deep golden or almost orange pollen of the fourth seg- 

 ment makes a very strong contrast. 



Genus BRACHYCOMA Rondani 



Brachycoma Rondani, Dipt. Ital. Prod., vol. 1, 1856, p. 69. 



Laccoprosopa Townsend, Trans. Arner. Ent. Soc, vol. 18, 1891, p. 365; 



Ins. Ins. Menst., vol. 3, 1915, p. 116. 

 Bomlolrachyooma Townsend, Ins. Ins. Menst., vol. 6, 1918, p. 157. 



BRACHYCOMA RUFICAUDA, new species 



Entirel}'- black except the fifth abdominal segment in female and 

 second genital segment of male, which are bright reddish-yellow. 



Male. — Front at narrowest one-fourth the head width (three meas- 

 ured 0.26, 0.26, and 0.27), the median stripe broad, black. Para- 

 frontals silvery but with dark reflections especially opposite antenna! 

 insertion ; frontals reaching level of arista ; paraf acials silvery above, 

 gi-ayish below, width at narrowest half that of third antennal joint, 

 about four large bristles and a few hairs on lower part near eye; 

 facial ridges bare except near vibrissae, which are at oral margin; 

 epistoma prominent; palpi black; cheek one-fourth of eye heights 

 Third antennal joint hardly twice the second, arista pubescent near 

 base, its second joint distinct but hardly elongated; back of head 

 not very bulging, with only black hair. 



Thorax black with four narrow stripes of white pollen, the outer 

 on the margin, the inner just mesad of dorsocentrals and extending 

 in some lights rather vaguely upon the sides of the scutellum; an- 

 other pair of stripes lie above the supraalar bristles and in rear view 

 extend across the suture anteriorly. Chaetotaxy: dorsocentral 3,3; 

 acrostichal 0,0; humeral 3; presutural 1; notopleural 2; supraalar 2; 

 intraalar 2; postalar 2; sternopleural 2,1; scutellum with two lateral 

 pairs, no apical, the di.sk with numerous upright slender hairs, no 

 post scutellum. Abdomen black with bluish reflection, viewed from 

 behind with four rows of silvery pollinose spots on second to fourth 

 segments; second segment with one median marginal pair of bristles, 

 third with marginal row of 10, fourth with marginal row of 12 or 

 more; venter black with four pairs of white pollinose spots, not very 

 distinct. First genital segment shining black, with a row of stout 

 bristles; second red with bristles and hairs not in rows on posterior 

 part. Inner forceps red at base, becoming black and slender and 

 curving forward and slightly outward to a sharp tip. Outer forceps 



» Proc. U. S. Nat. Mus., vol. 43, 1912, p. 363. 



