CHARLES P. ALEXANDER 247 



2. Wings nearly hyaline, not banded, only the costal cells yellowish. (Par- 



aguay) occulta Alexander** 



Wings yellowish, banded 3 



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



(Mexico) flninpennis Osten Sacken'^ 



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) opicalis sp. n." 



Genus MONGOMA Westwood 

 1881. Mongo77ia Westwood, Trans. Ent. Soc. Lond., 1881, 364. 

 Mongoma geniculata sp. n. 



Cross-vein r just before the fork of R2+3; wings with the veins seamed 

 with gray, tip not infuscated; 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. 



Praescutum dark brown without distinct darker markings; scutum with 

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

 scutellum and postnotum brownish black. Pleura pale yellowish, the 

 inesopleura 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 tip not distinctly infuscated. Venation, 

 see plate IV, fig. 7. 



Abdominal tergites dark brown, the lateral margins yellow; sternites 

 yellow. 



Habitat. — Bartica, February 18, 1913. 



Holotype, 9 , Bartica, February 18, 1913. 



Mongoma pallipes sp. n. 



Cross-vein r just before the fork of Ri+z', 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 j'cUowish. Antennae 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 



55 1914. occulta Alexander, Ent. News, xxv, 209, pi. ix, fig. 5. 



■■'^ 1873. flavipcnni^ Osten Sackcn, Mon. Diy)t. N. .\in.. iii, ix (supi)le- 

 raent). 



" 1914. apicalis, sp. n., this paper. ])\. iii. iig. 9. 



TRANS. AM. RNT. SOC, XL. 



