CHARLES P. ALEXANDER 237 



12. The wing membrane uniformly dark brown 13 



The wing membrane mostly hyaline, the darker markings small, limited 



or indistinct 14 



13. Mesonotal praescutum in front with a longitudinal shining black median 



stripe; femora blackish with a rust-red band beyond the base. 



(South America) schineri Enderlein^'' 



Mesonotal praescutum entirely bright ochraceous yellow, unmarked^ 

 with darker; femora uniformly yellowish without a rust-red ring. 

 (Brazil, Peru) flavithorax Wiedemann'* 



14. Thoracic dorsum shiny black without markings [rostrum very long 



and slender; wings hyaline with the tip infumed with brown, a 

 conspicuous seam along the cord]. (British Guiana) 



stygica sp.n.'" 

 Thoracic dorsum with more or less red or yellow 15 



15. Femora brown with a yellowish annulus before the tip [thorax yellow 



with brown stripes; wings a little yellowish, the tip scarcely 

 brown; abdomen brown and yellow; length of the cf about 7 mm.]. 



(Brazil) simplex Wiedemann^' 



Femora without a yellow annulus before the tip ; head reddish 16 



16. Thoracic dorsum reddish yellow without darker markings 17 



Thoracic dorsum more or less red but distinctly' marked with dark 



brownstripesorspots 18 



17. Large (d^, length, 10 mm. or over) ; legs pale yellow, the femora with a 



brown band beyond the middle [head dark in front, pale yellow 

 behind; brown markings on the wing consisting of a large rounded 

 dark brown stigma and an indistinct seam along the deflection of 



■ i24+5; abdomen light yellow]. (Panama) audax Alexander'* 



Small (cf , length, 4 mm.); legs uniformly brown beyond the base of 

 the femur [head blackishbrown; wings tinged with pale brown, the 

 stigmal spot well-defined, brown; costa clouded with brown to 

 the tip, some of the cord with brown seams; halteres brown; 

 abdomen blackish brown, the male hypopygium with many thorn- 

 like appendagesl. (Colombia) spinigera Schiner'^ 



18. Thoracic dorsum reddish yellow with three confluent black stripes 



that occupy nearly the whole mesonotum 19 



Thoracic dorsum reddish yellow with three dark spots [head reddish; 

 pronotum yellow; hind coxae reddish yellow like the other coxae; 

 wings hyaline without a dark basal spot; abdomen with the 

 basal tergites dark brown, the apical tergites yellowish] . (Peru) . 



fulgens Alexander^" 



" 1912. schineri Enderlein, Zool. Jahrb., xxxii, pt. 1, 71, 72. 



" 1821. flavithorax Wiedemann, Dipt, exot., i, 43, no. 3 (Limnobia). 



1* 1914. stygica, sp. n. this paper, pi. iii, fig. 6. 



" 1830. simplex Wiedemann, Aussereur. zweifl. Ins., i, 549 {Limnobia). 



" 1913. audax Alexander, Psyche, xx, 44, 45, ]A. 2, fig. d. 



1' 1868. spinigera Schiner, Xovara Reise, Dipt., i). 4-i. 



^° 1913. fulgens Alexander, Ent. Xew.?, xxiv, 440, pi. l(i. fig. 2. 



TRANS. AM. ENT. SOC, XL. 



