NORTH AMKRICAN DIPTKRA. 



arista is composed of numerous segments, the basal piece 

 of the complex third joint has necessarily fewer segments, 

 since both together never have more than eight. The 

 style, as the term is usually applied, is always terminal; 

 while the arista may be either terminal or dorsal, usually 

 the latter, and it may even be inserted close to the base 

 of the third joint. It is also apparent here, and this is 

 the rule among the Cyclorrhapha, that the basal position 

 is in reality due to the greater development of the under 

 side of the joint, by which the width has greatly exceeded 

 the length. The style is only rarely present in the Cy- 

 clorrhapha ( Ceria, Conops} , and in but few known instances 

 is the arista aborted in this suborder. 



Fij<. 6. Talarocera nigripennis, head of male from in front, much 



enlarged. 



The first two antennal joints, that is the scape, are, as 

 has been said, usually provided with hairs or bristles, 



