LONCHOPTERIDAE HYBOTIDAE. 29 



F know only one species of PLATYCNEMA, one species of CALLO- 

 MYIA, and two species of PLATYPEZA occurring in N". A. 



FAM. XXVII. LONCHOPTERIDAE. 



Charact. Three basal cells of moderate size, of nearly equal length ; fourth 

 longitudinal vein furcate and united with the fifth near the base. 

 Antennae with an apical bristle. Empodium wanting. 



This family is also founded on a single genus which cannot be 

 placed in any other family. Though in LONCHOPTERA the basal 

 cells are by no means large, yet their structure and the great deve- 

 lopment of the sixth longitudinal vein seems to prove that this 

 family should be reunited with one of those already mentioned. 

 However, by the form of its neuration and its anal parts it differs 

 so widely from them, that it is very difficult to state in what their 

 affinity consists. Mr. Walker has lately added the genus CADREMA 

 to the family of Lonchopteridce. 



LONCHOPTERA is found in N. A. 



FAM. XXVIII. HYBOTIDAE. 



Charact. Three basal cells complete, rather large, the third only a little 

 shorter than the second ; posterior transverse vein of the base 

 generally running perpendicularly or at a somewhat acute angle 

 into the sixth longitudinal vein, and thus not being parallel to the 

 posterior border of the wing ; third longitudinal vein frequently 

 furcate; anterior intercalary vein often wanting, posterior never 

 present. First joint of the antennse not much shortened, the third 

 more frequently with a bristle than with a style, the bristle some- 

 times dorsal instead of being apical. Empodium membranaceous 

 and linear; 



The three families : Hybotidse, Empidse and Tachydromidse run 

 into each other so insensibly, that it is very difficult to indicate 

 sharp limits between them. If we select this or that character as 

 being of greater importance, we shall always obtain a different result 

 as to these limits. I maintain the family Hybotidse only with the 

 view of falling in with the usual arrangement, since I am fully 

 satisfied that there is no sharp limit to be drawn between it and 

 that of the Empidse. For neither the more convex thorax, nor 

 the horizontal direction of the proboscis, nor the form and position 

 of the palpi, nor the simplicity or furcation of the third longitudi- 



