CHARLES P. ALEXANDER 239 



26. Thoracic dorsum with three complete dark brown stripes 27 



Thoracic dorsum without three dark brown stripes 28 



27. Wings broader, the tip not infuscated; femora j^ellow tipped with 



brown. (Eastern United States) ... .complexa Osten Sacken^' 

 Wings narrower, the tip narrowly infuscated; femora yellowish brown 

 at the tip and with a postmedial brown annulus. (Lesser An- 

 tilles; Guiana) annulata VVilliston^o 



28. Thoraxlight yellow with a dark narrow pleural stripe. (Central Amer- 



ica) pleuralis Alexander^' 



Thoraxwithout a pleural stripe 29 



29. Head and abdomen with metallic reflections; prothorax brownish; 



femora brownish black. (Cuba) chalybeiventris Loew^- 



Head gray without metallic reflections; prothorax dull yellow; femora 

 > dlow with the tips broadly brown. (Bolivia) 



jocosa Alexander^^ 



Genus ORIMARGA Osten Sac ken 

 1869. Orimarga Osten Sacken, Mon. Dipt. N. Am., iv, 120. 



Orimarga punctipennis sp. n. 



Thoiax and head bluish gray; legs very pale, almost whitish; wings 

 spotterl with brown. 



Male. — Length, 7 mm. ; wing, 4.4 mm. 



Robtrum rather elongated, dark brown, the palpi brownish black. An- 

 tennae with the basal segments light brown, the flagollum i)roken. Head 

 with a uniform light gray bloom. 



Thoracic dorsum brown with a thick blue-gray bloom. Pleura yellow- 

 ish brown. Halteres rather short, brown, more yellowish at the base. Legs 

 with the coxae and trochanters yellowish brown, the remainder very pale 

 whitish brown except the apical tarsal segments which are brown. Wings 

 almost hyaline, the veins brown; dark brown dots as follows: the largest 

 at the tip of .SV, others at the base of Rs, tip of Ri, and on cross-vein r, 

 basal deflection of 72^+5 and cross-vein r-m and faint marks on the basal 

 deflection of Cui and at the fork of (Jui and Mz. Venation: see pi. IV, fig. 3. 



Abdominal tergites dark brownish black, the sternites paler. 



Habitat. — Bartica, February 11, 1913. 

 Holotype, cf , Bartica, February 11, 1913. 



29 1859. cowplexa Osten Sacken, Proc. Acad. Xat. Sci. Phila, 1859, 223. 

 (genotype). 



30 1896. (umulnta Williston, Trans. Ent. Soc. Lond.. 1896. 290, pi. x, 

 fig. 63. 



3' 1913. pleuralis .\lexandcr, Psyche, xx, 45, 46. 



3- 1861. chalybeiventris Loew, Wien. Entomol. Monatschr., v, no. 2, 

 33, 34 (Rhamphidia). 



" 1913. iorosn Alexander, Ent. X<nvs, xxiv. 440, 441. pi. 16, fig. 3. 



TU.\N.S. AM. K.NT. SOC, XI.. (18) 



