92 OHIO BIOLOGICAL SURVEY 



68 E. tenax Unne. The "drone fly." Cosmopolitan, eveo^here 

 abundant from early spring to late autumn. 



69 E. transversus Wiedemann. Numerous specimens, I^akeville, 

 Columbus, Sandusky, Ira, Wauseon; first of April and last of August. 



Meromacrus Rondani 



70 M. acutus Fab. A male, Cincinnati, Sept. i, 1909 (Dury). See 

 Journal Cine. Soc. Nat. Hist. Vol. XXI, p. 62. 



Tropidia Meigen 



1 Femora black, at the tip testaceous; the hind femora below, near the base, 

 with a strong mammiform process, {male) *>namillata Loew (111., Kan., Neb.) 



2 Front and middle femora yellow on distal end; hind femora without such 

 process near the base quadrata 



3 Antennae large, reaching nearly to the oral margin, hind coxae of male with a 

 large obtuse spur *calcarata Willist (Mich., N.J.) 



7 1 T. quadrata Say. One female has a broad, strongly arcuate, black 

 band in the middle of the third segment, well separated from the margins, 

 expanded on the middle line in front. Two females are only about eight 

 millimeters long. Numerous specimens, Sandtisky, Columbus, Hinckley, 

 Wauseon; May 23 to Sept. 10. (Figs. 229, 233.) 



Helophilus Meigen 



1 Face jutting forward into a sharp cone conostomus 



Face not conically produced forwards 2 



2 Sixth longitudinal vein distinctly sinuous; light colored species, stripes of tho- 



rax distinct ?> 



Sixth vein nearly straight or only gently curved; antennae reddish-yellow... 4 



3 Front of female black pilose; front of male narrow above similis 



Front of female black pilose only near the ocelli ; front of male broad . . . .latifrons 



4 Abdomen elongate, cylindrical in the male • 8 



Abdomen oval; face yellow; dorsum of thorax with distinct light colored stripes 



5 



5 Third abdominal segment, except a small opaque spot in front, and the fourth, 



shining sub-metallic black bilinearis 



Third and fourth segments distinctly banded 6 



6 Hind femora yellow in the middle, abdomen predominately yellow. . .flavifacies? 

 Hind femora in large part black above; luteous fasciae of the abdomen broad, 



the first narrowly interrupted, the remainder entire 



^integer Loew(N. Y.N., J.) 



Hind femora with a black ring at the middle 7 



7 Arista wholly black; yellow of each of the principal abdominal segments di- 



vided into two moderately curved lunules divisus 



Arista black at the tip; abdomen with much yellow laetus 



