396 NORTH AMERICAN DIPTERA 



106. Sternopleural bristles situated in a nearly equilateral triangle, almost 



always three in number 107 



Stemopleurals not forming a nearly equilateral triangle, if only three 

 are present the lower one is decidedly farther from the anterior. . .111 



107. Dorsocentrals very weak, poorly differentiated Atherigona Rondani 



Dorsocentrals strong 108 



108. Anterior tibiae with a posterior bristle near or beyond the middle... 109 

 Anterior tibiae without posterior bristle except at apex. 



Lispocephala Pokorny 



109. Four stemopleurals, the posterior three in a straight line. 



Macrorchis Rondani 

 Three stei-nopleurals 110 



110. Posterior bristle on front tibiae very long, situated before the middle. 



Dialyta Meigen 

 Posterior bristle on front tibiae short, situated beyond the middle. 



Limnospila Schnabl 



111. Sixth vein very short, the seventh cui'\'ed strongly forward so that it 



would bisect the sixth only a little beyond the end of the latter. . .112 

 Sixth vein not unusually short, the seventh never curved so that it 

 would bisect the sixth 114 



Muscidse IV. — 46, Cordilura; 47, Liinnophora; 48. Phaonia; 49, Charadrella niacrosoma; 

 50, Phaonia; 51, Philornis sperinophilse ; 52, Lutzomyia latifrons; 58, Charadrella inacrosoma. 



