256 



W. WESCHE. 



any change in the position they now occupy among the Bibionidae, 

 though I consider this family the most specialized of the Nemo- 

 cera. 



TABLE IV. 



CHARACTERS OF THE GENITALIA IN THE BRACHYCERA AND CYCLORRAPHA. 



1 Invisible in preparations. 



" Indefinite, suggests affinities with Dolichopus. 



3 Transparent, only demonstratable by dissection. 



4 And theLeptidae are nearer type i than 2 or 3. They only approximate. 



If any reliance is to be placed on the genitalia, the Stratiomyidae 

 mu^t belong in group 3, since the male type clearly connects the 

 family with the Asilidae, Empidae and Dolichopodid?e. And the 

 condition of the mentum sustains this view, though character 

 of the leg pubescence is less decisive. The genitalia and venation 

 of the Tabanidae are so close that it seems impossible to separate 

 the family; both find their place in group 5. 



These points seem to show that group 3 is an artificial one; 

 nor does group 4 inspire me with confidence, since I can not 

 separate the Phoridae and the Lonchopteridae from the Asilidae, 

 Empididae and Dolichopodidae. Group 4 must be narrowed 

 down to the Cyclorrhapha, and even here I think that I can 

 trace the pedigree to group 5, if not to group I. 



