30 DIPTERA OF NORTH AMERICA. 



nal vein, nor the presence or absence of the anterior intercalary 

 vein are characters, on which whether we use them singly or in 

 any combination we can found a satisfactory or sharp defini- 

 tion of both families. The resemblance of some Hybotidae with 

 some Bombylidse cannot be denied, but their place will never be 

 doubtful if we consider, that in the Bombylidse the third basal cell 

 is open or only closed near the border of the wing, while in all 

 Hybotidse it always remains remote from that border. To the 

 family Hybotidse. may be referred : BRACHYSTOMA Meig., HYBOS 

 Fabr., SYNECHES Hal ( Pterospilus Rond. = Harpamerus 

 Big.), SYNDYAS Loew, STENOPROCTUS Loew, ACARTERUS Loew, 

 MEGHYPERUS Loew, OEDALEA Meig., EDTHYNETJRA Macq. (= An- 

 thalia Zett.), OCYDROMIA Meig., TRICHOPEZA Rond. on account of 

 of its near relation with Brachystoma and LEPTOPEZA Macq. on 

 account of its resemblance with Ocydromia. The two last genera 

 might as well be placed among the Empidse, since they agree with 

 them in having the posterior basal transverse vein parallel to the 

 border of the wing. 



The N. A. species which I possess belong to the following 

 genera: BRACHYSTOMA Meig., HYBOS Fabr., SYNECHES Walk., 

 SYNDYAS Loew, and LEPTOPEZA Macq. Mr. Walker also describes 

 a species which he believes to belong to the genus OCYDROMIA Meig. 



FAM. XXIX. EMPIDAE. 



Charact. Three basal cells complete, rather large, the third shorter than 

 the second ; posterior basal transverse vein parallel to the border of 

 the wing ; third longitudinal vein frequently furcate ; anterior in- 

 tercalary vein present, the posterior wanting. First joint of the 

 antennae not much shortened, third joint with an apical bristle 

 sometimes resembling a style. Empodium membranaceous and of 

 a linear form. 



The genera belonging to this family are : EMPIS Meig., PACHY- 

 MERIA Macq., ERIOGASTER Macq., APLOMERA Macq., RHAMPHO- 

 MYIA Meig., HILARA Meig., RAGAS Walk., GLOMA Meig., MICRO- 

 PHORUS Macq., HORMOPEZA Zett., ITEAPHILA Zett., MICROSANIA Zett., 

 and CYRTOMA Meig. 



The N. A. species known to me belong to the genera : EMPIS 

 Meig., PACHYMERIA Macq., RHAMPHOMYIA Meig., HILARA Meig., 



