39S NORTH AMERICAN DIPTERA 



129. Front with an outwardly directed orbital bristle, wide in both sexes 



(30) '. Platycoenosia Strobl 



Front without true orbital bristles, or they are not divergent; usually 

 narrow in males 130 



130. Parafrontals polished; frontal lunule shining white; thorax and abdo- 



men without pollen (9) *Ophyra Desvoidy 



Parafrontals pollinose on most of their length 131 



131. Hypopleura haired below the spiracle (11). 



fSpilaria Schnabl & Dziedzicki 

 Hypopleura bare below the spiracle 132 



132. Hypopleura haired in front of the spiracle (1, 10) fHelina Desvoidy 



Hypopleura bare in front of the spiracle 136 



133. Arista pubescent 131 



Arista with long rays (48, 50) JPhaonia Desvoidy 



134. Hypopleura bare in front of the spiracle 135 



Hypopleura haired in front of the spiracle Achaetina Malloch 



135. Prealar more than half as long as the following bristle. 



Neohydrotaea Malloch 

 Prealar less than half as long as the following bristle. 



§Hydrotaea Desvoidy 



* Malloch. 1923, Ann. Mag. Nat. Hist., xi, r. 664. 



t Malloch, 1920, Can. Ent., liii. p. 103. 



$ Malloch, 1923, Tr. Amer. Ent. Soc, xlviii, pp. 239—. 



§ Malloch, 1916, Bull. Brooklyn Ent. Soc, xi, p. 109. xiii. pp. 30-33. 



Muscidffi V. — 54, Philornis spermophilae ; 55, Dichsetomyia ; 56. Myospila meditabunda; 

 57, Ceiatinostoma ostiorum ; 58, Muscina stabulans; 59, Lutzoinyia latifrons; 60, Cordilura. 



