88 OHIO BIOLOGICAL SURVEY 



47 M. marginata vSay. A ver}- abundant species, variable in the 

 extent and distinctness of the black markings on the abdomen. Specimens at 

 hand from Columbus, Ira, Medina, Akron, Lakeville; May to vSeptember. 



48 M. polita vSa}'. Eight specimens, Columbus, Lakeville, Medina, 

 Portsmouth; late March to earl}- September. 



Sphaerophoria St. Fargeau and Serville 



1 Hypopygium large with a tuft of yellow pile below the globular part in 



front 2 



Hypopygium and its pileblackish; yellow thoracic margin distinct only to the 

 suture; abdomen all black except for a narrow, interrupted, translucent 

 fascia on the hinder part of the second, and a pair of large translucent quad- 

 rate spots on the front part of the third abdominal segments nigricauda 



2 Larger spacies about 10 mm. long; yellow thoracic margins distinct to the scu- 



tellum; black median stripe on front of female narrowing below; narrow 

 black fasciaon the oral margin in front; pecular color design on fourth and 



fifth abdominal segments in the male sp. 



vSmaller species 6 to 10 mm. the yellow thora cic margins distinct only to the 

 suture; black stripe on front of female widened below above the antennae, 

 black fascia on oral margin in front indistinct or wanting cylindrica 



49 S. cylindrica (Say). For descriptions of life-stages see Part II. 

 p., 59. Abundant, Lakeville, Columbus, Akron, Vinton, Ira; April 21 

 to October, especially abundant June and July. 



S. sp.? This form seems more or less distinct from cylindrica as 

 indicated above but it may be a variety of the former. The abdominal 

 color pattern suggests that it may be the ^. scripta Linne of Europe and 

 Canada. Numerous specimens, male and female, Eakeville, Ira, Colum- 

 bus; mid-June to mid-September. 



50 S. nigricauda Hine (Mss.) One male, Sandusky Hine, very dis- 

 tinct from the other species of the genus, 



Pelecocera Meigen 

 ^P. pergaudei^\\\s\.. (D. C.) 



Sphegina Meigen 



1 Front in female much longer than broad 2 



2 Fifth abdominal segment in female considerably broader than long; posterior 



part of abdomen in males, dark brown or black, marked with yellow or red- 

 dish; cross-bands interrupted or entire; hind femora dark brown at least on 



distal half. lobata 



Fifth abdominal segment in female but little broader than long .3 



3 Thorax more or less black; posterior part of abdomen in male reddish-brown 



unmarked; hind femora light brown or reddish-yellow on distal half 



rufiventris 



