CHARLES P. ALEXjVNDEK 247 



2. Win^s nearly hyaline, not banficd, only the costal cells yellowish. (Par- 



a..;uay) occulta Alexander" 



Winga yellowish, banded 3 



3. Wings with the banding confined to a narrow mark along the cord. 



(Mexico) flaripennia Osten Sackcn" 



Wings with the apex broadly banded, the middle crossband narrow, 

 darker brown; the basal band not suffusing the anal angle of the 



wings. (British Guiana) apicnlis sp. n." 



Genus MONGOMA Westwood 

 1881. Mongoma Westwood, Trans. Knt. Soc. Lond., 1881, 364. 

 Mongoma geniculata sp. n. 



Cross-vein r just before the fork of lls+s; wings with the veins seamed 

 with gray, tip not infuscatcd; legs black with the tip of the femur and the 

 base of the tibia narrowly white, the tarsi brown. 



Female. — Length, 10.8 mm. ; wing, 7.7 mm. 



Rostrum and palpi brown, the latter darker; Antennae dark brownish 

 black. Head brown. 



Praescutuni dark brown without distinct darker markings; scutum with 

 the lobes dark brownish black, the median area paler, more yellowish; 

 scutellura and postnotum brownish black. Pleura pale yellowish, the 

 mesoplcura a little infumed with brown. Halteres brown. Legs with the 

 coxae and trochanters yellowish brown; femora brownish black, the tip 

 narrowly white; tibiae dark brown, the extreme base whitish; tarsi dark 

 brown. Wings subhyaline, the stigma prominent, oval, dark brown; veins 

 broadly seamed with gray, the ti^ not distinctly infuscated. Venation, 

 see plate IV, fig. 7. 



.Vbdominal tergitcs dark brown, the lateral margins yellow; sternitcs 

 yellow. 



Habilat.—Bartma., February 18, 1913. 



Holotype, 9, Bartica, February 18, 1913. 

 Mongoma pallipes sp. n. 



Cross-vein r just before the fork of /?2-).3; tip of wing infuscated and the 

 veins seamed with gray; legs with the tips of the femora broadly white, the 

 extreme base of the tibiae similar; hind legs, only, with the tarsi and the 

 tip of the tibiae white, the remaining tarsi brown. 



Male. — Length, 9.4 mm.; wing, 7.3 mm. 



Rostrum yellowish, .\ntennac broken. Head dark brown, more yellow- 

 ish behind. 



Praescutum light yellowish brown, more brownish behind near the su- 

 ture ; scutum with the lobes dark brown, the median space pale ; scutellum and 



" 1914. occulta Alexander, Ent. News, xxv, 209, pi. ix, fig. .5. 



" 1873. flavipennis Osten Sacken, Mon. Dipt. X. .Vni., iii, ix (supple- 

 ment). 



" 1914. apicalis, sp. n., this paper, i)l. iii. fig. 9. 



TRANR. AM. ENT. SOr.. XI.. 



