MYOPIDAE. 27 



founded was a composition of a body of a Microdon with the head 

 of a Conops. The genus Toxomerus Macq. has not been mentioned 

 in the above list, it being quite untenable. I judge Dimeraspis 

 Newm. to be identical with Microdon. Psarus has been omitted, 

 because the species described under this name must be placed in 

 other genera. The statement of Humerus Meig. occurring in X. 

 A. is founded merely on an observation of Walker, and therefore 

 requires further confirmation. Macquart records a N. A. species 

 of the genus Psilota Meig., but this genus having been misunder- 

 stood by most authors, I do not venture now to mention it among 

 those truly represented in N. A. 



Fam. XXIII. MYOPIDAE. 



Ckaract. — Three basal cells large, the third closed, more or less remote 

 from the posterior border ; all longitudinal veins simple ; no inter- 

 calary vein. Eyes in both sexes broadly separated ; proboscis, with 

 few exceptions, much prolonged; maxillae small ; the third joint of 

 the antenna? with an apical style or a thick dorsal bristle. Hypo- 

 pygium symmetrical, turned under the abdomen. Empodium 

 wanting. 



Omitting the untenable genera into which the genus Conops has 

 been subdivided by Kondani and the genus Myopa by Perris, we 

 mention here the genera: Conops Linn., Pleurocerina Macq., 

 Zodion Lair., Myopa Latr. and Stachinia Macq. 



This family has been divided by some authors into two families: 

 Conopidoe and Myopidsc, the former containing those genera which 

 have an apical style on the antenna?, the latter being characterized 

 by a dorsal bristle of the antenna}. I cannot approve of this divi- 

 sion at all, since the difference between a style and a bristle, and 

 the difference of an apical and a dorsal position, according to all 

 experience, only furnishes characters of very inferior value for the 

 systematic arrangement, as we see in the families Stratiomydse, 

 Bombylidae, Syrphidse, Hybotidse, Dolichopidee, etc., where this 

 organ is sometimes apical, sometimes dorsal. We might as well 

 form two families on account of the proboscis being either straight 

 or geniculated. But the conspicuity of the difference in the struc- 

 ture of the antenna) may serve to form two sections in the family, 

 Conopina and Myopina, the former of which would contain the 

 genera Conops and Pleurocerina, the latter the genera Zodion, 

 Myopa, and Stachynia. 



