FLIES OF GENUS RIVELLIA — NAMBA 37 



D. E. Hardy; 1 cf , July 7, 1939, P. B. Lawson). Canada: Water- 

 town Lake Park, Alberta (19, Icf, July 26, 1946, C. E. Mickel). 

 Florida: Lacoochee (IcT, Aug. 9, 1939, D. E. Hardy); Wakulla 

 (Id', July 10, 1939, D. E. Hardy). Georgia: Adel (19, Aug. 11, 1939, 

 J. D. Beamer) ; Austell (1 cT, Aug. 27, 1910) ; Billy's Island, Okefenokee 

 Swamp (IcT, June, 1912); Griffin (299, 26"^, Aug. 12, 1939, R. H. 

 Beamer; 19, 2cf cT, Aug. 12, 1939, E. G. Wegenek; 299, Aug. 12, 1939, 

 A. T. Hardy; Id', Aug. 12, 1939, J. D. Beamer); Perry (599, ^^d", 

 Aug. 12, 1939, D. E. Hardy) ; Tifton (19, Aug. 11, 1939, R. H. Beamer) ; 

 Waycross (Id^, May 8, 1911). North Carolina: Goldsboro (Id', 

 July 20, 1946, M. W. Wing); Raleigh (Icf, early July, Metcalf; 19, 

 July 8, 1938, Wilson). (Deposited in SEC, UM, NC, USNM, and CU.) 

 Remarks: The members of this species are among the smallest 

 Rivellia of America north of Mexico. R. maculosa can be distinguished 

 from the other species by the reduced wing banding, obsolete anal 

 angle of wing, and the male genitalia. 



Rivellia occulta Van Der Wulp 



Figure S,d-g 



Rivellia occulta Van Der Wulp, 1898, p. 382, pi. 10, fig. 8.— Hendel, 1914a, p. 178, 

 pi. 2, fig. 33; 1914b, pi. 2, fig. 33.— Cresson, 1924, p. 229. 



Type locality: Chilpancingo (4,600 ft.) and Omilteme (8,000 ft.), 

 both in Guerrero, Mexico. Location of type unknown. 



Male: Body length about 2.7 mm. 



Head: Frons yellow toward antenna, brown toward vertex; upper 

 fron to-orbital plates and ocellar triangle blackened. Face with dorsal 

 half pruinose, ventral half shining, rugulose, pale yellowish gray; 

 parafacials and part of orbits ventral to each eye concolorous with 

 face. Antenna with first and second segments yellow; third slightly 

 blackened outside, remainder yellow, the tip pointed anteriorly. 

 Anteclypeus concolorous with ventral portion of face, rugulose. 

 Palpi yellow. Poster anium dark brown, rather densely pruinose. 



Thorax: Mesonotum dark brown; strong humeral and posterior 

 dorsocentral setae present. Scutellum and postscutellum concol- 

 orous with mesonotum. Plem-a dark brown, mostly shining. Meso- 

 pleuron with scattered pale setae on posterior half; posterior half 

 pruinose. Sternopleuron with broad medial pruinose band which 

 extends from the ventral corner to the dorsal margin where it becomes 

 continuous with pruinose band on mesopleuron; disc with scattered 

 pale setae. Disc of pteropleuron with scattered pale setae and one 

 prominent black seta ventral to subalar. Hypopleuron with shining 

 central spot, remainder pruinose. Laterotergite completely and 

 densely pruinose. Prosternum pale yellow. 



867314—56 2 



