FLIES OF GENUS RIVELLIA — NAMBA 61 



positing in a dried-up flower. The eggs are milky white in color and 

 oblong (length about 1.4 mm., width 0.5 mm.) with round ends. 

 Subsequent investigations disclosed no further ovipositing activity 

 and no eggs. No larvae were discovered. 



Rivellia viridulans Robineau Desvoidy 



FiGUKE 5,d,e 



Rivellia viridulans Robineau Desvoidy, 1830, p. 729. — Loew, 1873, p. 88, pi. 8. 

 fig. 4.— Hendel, 1914a, p. 181.— Cresson, 1924, p. 226. 



Type locality: North America. (The type "d^truits d^finitive- 

 ment," according to E. Sdguy, in litt.) 



Males: Body length 3.6-5.7 mm.; wing length 2.6-4.0 mm. 

 Genitalia (fig. 5,e) with apical part of aedeagus consisting of a bulbous 

 base and two long filamentous terminal tubes which are about one 

 and a half times the length of basal part of aedeagus; cerci barely 

 extend beyond proc tiger. Otherwise shnilar to R. melliginis. 



Specimens examined: Georgia (IcT): Yonah Mountain; June 10. 

 Illinois (1 cJ'): Algonquin; no date. Iowa (1 cf ): Polk City (4 miles 

 northeast of Alleman); June. Massachusetts (Icf): Woods Hole; 

 July 12. Mississippi (Id^): Oxford; May. Missouri (Icf): Park- 

 ville; June 25. New Jersey (Icf): Ramsey; July 6. New York 

 (64cf cf): Babylon (Long Island), Cold Spring Harbor (Long Island), 

 Dix Hills (Long Island), East Queens, Farmingdale (Long Island), 

 Flushing, Islip (Long Island); May 15-Aug. 15. North Carolina 

 (5crc?'): Fayette ville, Henderson ville, Raleigh, Valley of Black 

 Mountains; June 12-July 17. Ohio (6cfcf): Summit County; 

 June 19-28. Virginia (2d^(^): Dixie Landing, Shenandoah Na- 

 tional Park; May 25-June 20. 



Remarks : This species is very closely related to R. melliginis. The 

 males of the two species can be separated by the difference in lengths 

 of the terminal tubes of the aedeagus, and the extent by which the 

 cerci extend beyond the proctiger. The terminal tubes in R. viridulans 

 are about one and a half times and in R. melliginis about three times 

 the length of the basal part of the aedeagus. In R. viridulans the 

 cerci barely extend beyond the proctiger, whereas in R. melliginis 

 they extend beyond the proctiger by about the length of the proc- 

 tiger. I am unable to separate the females of these species. 



In the past R. melliginis has been confused with this species. I 

 have seen the type of R. melliginis and consider it a distinct species. 

 Mr. E. Seguy has kindly informed me that the type of R. viridulans 

 is "detruits definitivement." The original description of R. viridulans 

 offers no information which will permit separation of these two species. 

 Since, however, the species considered here is more common than 



