46 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



Laffoon); Lake Amana (IcT, June 23, 1928, G. O. Hendrickson) ; 

 Linn County, Palisades-Kepler State Park (1 9 , July 7, 1950, Laffoon, 

 Slater, Hicks). Kaksas: Douglas County (1 cf , "900 ft.," May); 

 LawTence (3 cf d', 1 9 )( 1 9 , 1 cf, J. M. Aldrich). Michigan: Detroit 

 (Id', Juno 11, 1938, G. Steyskal). Minnesota: Mississippi Bluff, 

 one-half mile north of state line, Houston County (Id^, May 30, 

 1941); Ramsey County (Id^, June 16, 1951; 85 9 9, 70 d'd', June 20, 

 1951; 19, Id', June 20, 1951, on same pin; 29 9, Id", June 25, 

 1951; 2 9 9, 3d' d', June 29, 1951; 2 9 9, Id^, July 2, 1951; 29 9, 

 1 d", July 18, 1951, all collected by R. Nainba); St. Anthony Park, 

 Ramsey ^County (49 9 9, 34 d'd', June 18, 1952, R. Namba; 8 9 9, 

 4d' d', June 26, 1952) ; University Farm, Ramsey County (1 d^, July 4, 

 1951, R. Namba); South Minneiska, John Latsch State Park (1 9, 

 May 31, 1951, R. Namba). Mississippi: Utica (Id", Aug.). New 

 York: Ithaca (299, Id', July 9, 1904); Lancaster (1 9, June 4, 1911, 

 and 1 d", June 8, 1912, M. C. Van Duzee). Quebec: Abbotsford (1 9, 

 June 11, 1936, and 1 9 , Aug. 24, 1936, G. Shewell); Farnham (Id*, 

 July 16, 1935, G. Shewell). (In UM, GS, CU, USNM, SEC, CAS, 

 AMNH, ISC, INKS, EU, and SCW.) 



Remarks: This species can be distinguished from the other Rivellia 

 by the presence of strong humeral and posterior dorsocentral setae, 

 the sharp wedgelike hyaline area in the first basal cell, and the male 

 genitalia. 



The members of this species were found abundantly on Apios 

 americana Medic. 



This species is affectionately dedicated to my wife Winifred. 



Rivellia variabilis Loew 



Figure 9,a-d 



Rivellia variabilis Loew, 1873, p. 91, pi. 8, fig. 6.— Hendel, 1914a, p. 181.— 

 Cresson, 1924, p. 226. 



Type locality: District of Columbia (MCZ). 



Males: Body length 4.2-6.0 mm., wing length 3.2-4.3 mm. 

 Strong humeral setae present, posterior dorsocentral setae absent. 

 Genitalia (fig. Q,c,d) \vith apical part of aedeagus consisting of 

 an oblong base which from dorsal view has subparallel margins 

 basally, converging little apically, from lateral view mth dorsal 

 margin angular, ventral margin relatively straight, and with two 

 filamentous terminal tubes which are subequal in length to base. 

 Otherwise, except for coloration, essentiall}^ similar to R. wimftedae. 



Females: Body length 4.3-6.0 mm., v/ing length 3.5-4.6 mm. 



Variations: As suggested by its name, tliis species is quite variable. 

 The variation in general coloration is from yellow to pitch black. 



