FLIES OF GENUS RIVELLIA — NAMBA 53 



ventral corner, a pruinose medial band extending from this spot to 

 dorsal margin of sternopleuron ; disc with few scattered pale setae. 

 Disc of pteroplem'on with few scattered pale setae, one black seta 

 present ventral to subalar. Hypopleuron with small shining central 

 spot, remainder pruinose. Laterotergite completelj'" and densely 

 pruinose. Prosternum dark brown. 



Thoracic appendages : Legs wholly yellow. 



Wing (fig. 5,/) length 2.4 mm. Bands dark brown. First and sec- 

 ond bands separated at costal margin, slightly oblique to costal mar- 

 gin; fii"st band does not enter discal cell, ends at fourth vein. Third 

 band perpendicular to costal margin, broadened at third vein. Fourth 

 band consists of spot at tip of third vein, not connected to third band. 

 The part of first basal cell contiguous to second basal cell very faintly 

 banded at basal half. Section of fourth vein proximad of anterior 

 crossvein with very slight bend. Halteres bro^^ii. 



Abdomen: Tergites shining, slightly rugose, black. Disc of first 

 tergite with pale setae. Genitalia (fig. 5,h,i) with apical part of 

 aedeagus bearing a horn on dorsum of base, a flattened finlike struc- 

 ture laterally on each side of base, and two short filamentous termmal 

 tubes. 



Allotype: Female. Body length about 3.9 mm.; wing length 3.0 

 mm., width 1.7 mm. Frons brownish yellow. Hind tibiae brownish 

 yellow. Front tarsi blackened slightly from third segment, hind tarsi 

 with fifth segment slightly blackened. Thii'd band of wing not broad- 

 ened conspicuousl;y at third vein. Abdominal tergites and ovipositor 

 sheath dark brown. Otherwise similar to holotype. 



Paeatypes: 24 males, 14 females. Bod37" length, males and females, 

 3.2-4.2 mm.; wing length, males 2.4-3.0 mm., females 2.4-3.3 mm. 

 In both sexes thorax and abdominal tergites sometimes black; sterno- 

 pleuron sometimes without medial pruinose band ; fourth band some- 

 times narrowly joined to third band at costal margin. Otherwise 

 essentially similar to holotype or allotype. 



Specimens: Holotype, cf, College Station, Tex., Apr. 21, 1943, 

 H. J. Reinhard (TAM). Allotype, 9, same data as holotype. Para- 

 types: Arkansas: Fayetteville (1 cT, June 22, 1907). Texas: College 

 Station (2cf cf, May 14, 1923; Id", May 3, 1931; 499, 4cf cf, Apr. 

 21, 1932; 299, 5cf d', May 1, 1932; Icf, Apr. 13, 1943; 599, 6 d^o', 

 Apr. 21, 1943; Icf, Apr. 30, 1943; 19, May 1, 1947; 19, May 7, 1947; 

 2crcr, May 15, 1947; 19, Icf, May 11, 1947, on same pin; all col- 

 lected by H. J. Reinhard) . (Deposited m TAM, CU, USNM, and UM.) 



Remarks: This species appears to be related to R. maculosa and 

 R. vaga. Its full wing banding, which is similar to that of R. vaga, 



367314—56 3 



