108 



NORTH AMERICAN DIPTERA. 



tiuge of metallic- blue; no goldeu pile on the second segment ; the 

 alul.ie, the lateral angles and the root of the wing blackish-brown, 

 and the posterior margin brownish-hyaline. 



Fi£ 



EXPLANATION OF PLATE L 



1. Htrauzia longipennis, variety, wing. 



