FLIES OF GENUS RIVELLIA — ^NAMBA 45 



on ventral margin and a narrower strip on posterior margin; disc 

 with scattered, weak, pale setae. Disc of pteropleuron with scattered, 

 weak, pale setae, few black setae present ventral to subalar. Hypo- 

 pleuron with shining disc, borders narrowly pruinose. Lateroter- 

 gite completely and densely pruinose. Prosternum black. 



Thoracic appendages: Front legs: Coxae with black spot on out- 

 side at base, remainder yellowish brown; femora with distal one- 

 thu-d of inside brownish yellow, remainder black; tibiae brownish 

 yellow; tarsi blackened from second segment, first segment yellow. 

 Middle legs: Coxae black ; [femora with 'distal one-third of outside 

 brownish yellow, remainder black; tibiae yellowish at extreme tip, 

 remainder black; tarsi slightly blackened from third segment, re- 

 maining segments yellow. Hind legs: Coxae, femora, and tibiae 

 black; tarsi blackened from second segment, remaining segments 

 yellow. 



Wing (fig. 9,e) length 3.7 mm., width 1.6 mm. Bands dark brown. 

 First and second bands narrowly separated at costal margin; third 

 and fourth bands narrowly joined at costal margin. The part of 

 first basal cell contiguous to second basal cell banded at base ante- 

 riorly, the hyaline area contiguous to fourth vein sharply wedgelike 

 to base of second basal cell. Section of fourth vein proximad of 

 anterior crossvein with definite bend. Halteres dark brown. 



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

 with pale setae. Genitalia (fig. 9,g) with apical part of aedeagus 

 consisting of a laterally flattened base bearing on the dorsum a sharp- 

 pointed, curved, apically du-ected horn and two filamentous terminal 

 tubes which are little longer than length of basal part of aedeagus. 



Allotype: Female. Body length 5.5 mm.; vang length 4.2 mm., 

 width 1.7 mm. Front femora with inside almost wholly brownish 

 yellow; middle tibiae wholly brownish yellow. Ovipositor sheath 

 black. Otherwise similar to holotype. 



Pakatypes: 128 males, 166 females. Body length of males 4.3- 

 6.2 mm., of females 4.5-6.3 mm.; wing length of males 3.5-4,3 mm., 

 of females 3.7-4.5 mm. In both sexes general body color varies from 

 brown to black; also in both sexes sometimes all legs wholly yellow 

 or brownish yellow. Otherwise similar to holotype or allotype. 



Specimens: Holotype, cT, Sucker Lake, Ramsey County, Minn., 

 June 18, R. Namba (UM). Allotype, 9, same data as the holotype. 

 Paratypes: Georgia: Atlanta (19, Aug. 10, 1932, P. W. Fattig); 

 Hiawassee (1 cf , June 16, 1945, P. W. Fattig). Illinois: Champaign 

 (19, June 22, 1888, Marten-Hart, "14505"; 2 99, July 2, 1890, 

 Marten-Hart, "15784"); Galena (19, June 29, 1892, Hart-Shiga, 

 "18377"); Monticello (1 9 , July 2, 1914); Parker (1 9 , June 4, 1913). 

 Iowa: Boone County, Ledges State Park (1 9, July 17, 1951, Jean 



