50 PROCEEDINGS OF THE NATIONAL ]MUSEUM vol. loe 



Rivellia vaga, new species 



Figure l,d-f 



Holotype: Male. Body length about 3.3 mm. 



Head: Frons yellowish brown; upper fronto-orbital plates and 

 ocellar triangle blackened. Face with dorsal half pruinose, ventral 

 half shining, smooth, yellowish brown; parafacials and part of orbits 

 ventral to each eye brownisli yellow. Antenna with first and second 

 segments yellow inside, blackened outside; third segment blackened 

 at tip and on outside, remainder yellow, the tip pointed anteriorly. 

 Anteclypeus dark brown. Palpi yellow. Postcranium black, pruinose. 



Thorax: Mesonotum black; strong humeral and posterior dorso- 

 central setae present. Scutellum and postscutellum concolorous 

 with mesonotum. Pleura dark bro^\Ti, mostl}^ shining. Meso- 

 pleuron with scattered pale setae on posterior half; pruinose spot at 

 dorsal posterior corner in form of rectangle, one side extending two- 

 thirds distance to ventral posterior corner, the other side extending 

 about half way to anterior spiracle. Sternopleuron mth ventral 

 corner pruinose; disc with few scattered pale setae. Disc of ptero- 

 pleuron with few scattered pale setae, one black seta present ventral 

 to subalar. Hypopleuron wdth small shining central spot, remainder 

 pruinose. Laterotergite pruinose. Prosternum black. 



Thoracic appendages: Legs wholly yellow except for fore tarsi 

 which are blackened from third segment. 



Wing (fig. l,d) length 2.2 mm., width 0.9 mm. Bands dark 

 brown. First and second bands separated at costal margin, slightly 

 oblique to costal margin; first band does not enter discal cell, ends at 

 fourth vein. Third band perpendicular to costal margin. Third 

 and fourth bands very narrowly joined at costal margin; fourth 

 band greatly broadened at tip of thu'd vein. The part of first basal 

 cell contiguous to second basal cell faintly banded at basal half. 

 Section of fourth vein proximad of anterior crossvein ^vith very slight 

 bend. Hal teres brownish j^ellow. 



Abdomen: Tergites shining, slightly rugose; first three tergites 

 brownish, remainder black. Disc of dorsum of first tergite with 

 pale setae. Genitalia (fig. 1,/) with apical part of aedeagus con- 

 sisting of a cone-shaped base bearing on the dorsum a blunt horn, and 

 two filamentous terminal tubes which are subequal in length to basal 

 part of aedeagus. 



Allotype: Female. Body length about 3.6 mm.; wing length 2.5 

 mm., width 1.0 mm. Legs wholly yellow. Abdominal tergites dark 

 brown except for two large yellowish lateral spots on second tergite 

 and two smaller yellowish lateral spots on third tergite; ovipositor 

 sheath dark brown. Otherwise similar to holotype. 



