32 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lue 



few black setae present ventral to subalar. Hypopleuron with shining 

 central spot, remainder prninose. Laterotergite completely pruinose. 

 Prosternum brownish yellow. 



Thoracic appendages: Front and middle legs yellow, except for 

 tarsi which are slightly blackened from fourth segment. Hind legs 

 with coxae and femora yellow; tibiae yellowish brown; tarsi very 

 sUghtly blackened from fourth segment, remaining segments j^ellow. 



Wing (fig. 8,a) length 3.0 mm., width 1.5 mm. Bands brown. 

 First and second bands separated at costal margin, joined in discal 

 cell; third and fourth bands distinctly joined at costal margin. Second 

 and third bands appear perpendicular to costal margin. The part 

 of first basal cell contiguous to second basal cell completely banded. 

 Section of fourth vein proximad of anterior crossvein with very slight 

 bend. A hyaline spot present around junction of second and third 

 veins. Halteres brownish yellow toward base, remainder brown. 



Abdomen: Tergites shining, rugose, dark brown, somewhat lighter 

 toward base of abdomen. Disc of fb-st tergite with pale setae. 

 Genitalia (fig. 8,c) with apical part of aedeagus consisting of an apically 

 tapered base and two long filamentous terminal tubes about nine 

 times the length of basal part of aedeagus. 



Allotype: Female. Body length about 4.7 mm. Frons reddish 

 brown; postcranium dark brown. Thorax dark brown; pruinose 

 triangle on mesopleuron more extensive, one side reaches the ventral 

 posterior corner and the other side reaches the anterior spiracle. 

 Front legs: Coxae, femora, and tibiae yellowish brown; tarsi blackened 

 slightly from second segment, remaining segments yellow. Middle 

 legs: Coxae yellowish brown; femora yellowish toward tip, remainder 

 brown; tibiae brown; tarsi slightly blackened from third segment, 

 remaining segments yelloAV. Hmd legs: Coxae and tibiae brown; 

 femora yellowish at tip, remainder brown; tarsi slightlj^ blackened 

 from third segment, remaining segments yellow. Abdominal tergites 

 black; ovipositor sheath black. Otherwise similar to holotype. 



Specimens: Holotj^pe, cf, Mountain Park, N. Mex., June 27, 1940, 

 R. H. Beamer (SEC); allotype, 9, Ruby, Ariz., July 27, 1941, E. L. 

 Todd (SEC). 



Remarks: The important diagnostic characters of this species are 

 the peculiar banding of the wings, the additional pair of strong setae 

 anterolateral to the posterior dorsocentral setae, and the male genitalia. 



Rivellia australis, new species 



Figure 7,e-g 



Holotype: Female. Body length about 3.5 mm. 

 Head: Frons reddish brown; upper fronto-orbital plates and ocellar 

 triangle blackened. Face with dorsal half pruinose, ventral half 



