FLIES OF GENUS RIVELLIA — N.\MBA 57 



blackened. Hind legs: Coxae black; femora and tibiae yellowish at 

 extreme tip, remainder black; tarsi blackened from fourth segment, 

 remaining segments yellow. 



Wing (fig. 4,i) length: Males 2.5-3.4 mm., females 2.6-3.4 mm. 

 Bands dark brown or black, not as narrow as those of R. metaUica. 

 First and second bands narrowly separated at costal margin; third 

 and fom'th bands narrowly joined at costal margin. Costal cell 

 banded; the part of first basal cell contiguous to second basal cell 

 completely hyaline or at most very faintly banded basally. Section 

 of fourth vein proximad of anterior crossvein with slight bend. 



Abdomen: Tergites rugose ; otherwise similar to those of R. metallica. 

 Aedeagus similar to that of R. metallica; however, apices of surstyli 

 (fig. 4,j) dift'erent in shape from lateral view. Ovipositor sheath con- 

 colorous with abdominal tergites. 



Specimens examined: Connecticut (1 cT): Avon; June 21. Illi- 

 nois (499, TcJ'cr): Algonquin, no date; Monticello, June 21. Iowa 

 (599): Ames, Britt, County 3 ; May 31-June 19. Manitoba (19, 2 d' d'): 

 Aweme, Dauphin, Holland; Juno 18-July 14. Michigan (3699, 

 26cf cf): Bay County, Cheboygan County, Chnton County, Detroit, 

 East Lansing, Grand Rapids, Gratiot County, Ionia County, Lapeer 

 County, Midland County, Monroe, Nottawa, Rose Lake, Saginaw 

 County; May 21-Aug. 13. Minnesota (38899, 223 6^0^): Anoka 

 County, Chisago County, Cushing (Fish Trap Lake), Fort Snelhng, 

 Highway 26, 3 miles northeast of Eitzen (Houston County), Highway 

 26, 3 miles north of Hokah (Houston County), Mississippi Bluff, 

 one-half mile north of state line (Houston County), Itasca State Park, 

 Kanabec County, Kittson County, Lake Minnetonka, Lake Vadnais, 

 Laporte, Middle River, Norman County, Olmstead County, mouth 

 of Snake River (Pine County), Plummer, Oak Forest, Snail Lake, 

 St. Anthony Park, Sucker Lake, University Farm, Washington 

 County, White Bear; Mar. 9-Aug. 9. New Hampshire (Id^): 

 Center Harbor; July. New Jersey (499): Brookside (Morris 

 County), Ne\^1foundland, Ramsey; May 28-July 6. New York 

 (1999, lOcfcf): Canajoharie, Charlotte, Flatbush (Long Island), 

 Ithaca, Jamaica (Long Island), Lancaster, Mosholu, Pocantico Hills, 

 Rome, Tuxedo (Station for Study of Insects); May 30-July 15. Ohio 

 (Ic^): Summit County; June 9. Ontario (2799, 21cfcf): An- 

 caster, Centreville, Ganaoque, Jordan, Normandale, Orillia, Ottawa, 

 Simcoe, Tillsonburg, Toronto, Vineland; June 7-July 22. Quebec 

 (4299, 22(1^0"): Abbotsford, Aylmer (Queens Park), Chambly 

 County, Fairy Lake, Hull, He de Montreal, Missisquoi Bay, Rouville 

 County, St. Johns County, Wakefield; May 1-Aug. 24. South 

 Dakota (Icf): Brookings. 



