60 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



lowish; tibiae black basally, 3"ellowish toward tip; tarsi blackened 

 from second segment, remaining segments yellow. Middle legs: 

 Coxae black; femora black, extreme tip sometimes yellowish; tibiae 

 black, sometimes yellowish toward tip; tarsi blackened from third 

 segment, remaining segments yellow. Hind legs: Coxae, femora, 

 and tibiae black; tarsi blackened from third segment, remaining 

 segments yellow. 



Wing (fig. 5,0..) length 3.4-4.0 mm. Bauds black. First and 

 second bands separated at costal margin; third and fourth bands 

 narrowly joined at costal margin. The part of first basal cell con- 

 tiguous to second basal cell v/ith basal two-thirds banded, with semi- 

 cu'cular hyaline spot anterior to apex of second basal cell. Section 

 of fourth vein proximad of anterior crossvein with definite bend. 

 Halteres j^ellowish brown. 



Abdomen: Tergites shining, rugose, blackish blue. Disc of first 

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

 aedeagus consisting of a bulbous base and two long filamentous ter- 

 minal tubes about three times the length of basal part of aedeagus; 

 cerci extend beyond proctiger by about the length of proctiger. 



Females: Since I cannot distinguish between the females of this 

 species and R. viridulans, only females collected by me in the same 

 local population at the same time with the males of this species are 

 considered: Bod}^ length 4.0-5.5 mm.; wing length 3.6-4.4 mm.; 

 ovipositor sheath black. Otherwise similar to males. 



Specimens examined: District of Columbia (Icf): Anacostia; 

 May 13. Georgia (2 cf c?) : Neel Gap (Yonah Mountain) ; June 5-10. 

 Illinois (2 cT cf) : Meredosia; May 28. Iowa (2 o" cf) : Ames, Ledges 

 State Park; May 2G-June 19. Michigan (19, 3d^cf): Mendon, 

 Nottawa, northwestern Branch Count}^, Leelanau County, Muskegon 

 County; May 28-Aug. 2. Minnesota (1299, 13cfcf): Olmsted 

 County, St. Paul (University Farm) ; May 26-June 29. New Jersey 

 (ScfcT): Alpine, Trenton, Wenonah; June 8-24. New York 

 (42cf cf ): Bab3doii (Long Island), Cold Spring Harbor (Long Island), 

 Gowanda, Ithaca, Pelham; May 27-June 30. Ohio (2 cf cT) : Summit 

 County; June 23-28. Ontario (2d'cf): Prescott, Walsh; July 1-6. 

 Pennsylvania (Icf): Benvenuo; June 4. South Carolina (IcT): 

 Rocky Bottom (Pickens County); June 1. Wisconsin (IcT): Madi- 

 son; Jul}^ 27. 



Remarks: Asa Fitch (1855) vividly described the activity of the 

 adults of this species on apple, particularly its feeding activity on the 

 "honey dew" exuded by the "apple plant lice." 



All specimens of this species collected by me were found on black 

 locust (Robinia pseudo-acacia L.). One female was observed ovi- 



