106 KNTO.MOLOCICA!, NKWS | XXxii, '21 



A Synopsis of the Genera of the Anthomyiid Sub- 

 family Coenosiinae (Diptera). 



By J. R. MALLOCH, Urbana, Illinois. 



The members of this subfamily very closely resemble those 

 of Phaoniinae, possessing in common with them the following 

 characters : scutellum bare below ; ventral surface of prothorax 

 with the chitinised plate between and cephalad of the fore 

 coxae elongate, not broadly, triangularly dilated anteriorly, so 

 that there is a large membranous area on each side of the 

 plate ; hind tarsus rarely with an outstanding setula near base 

 on ventral surface of basal segment. 



Characters which distinguish species of the subfamily from 

 Phaoniinae are as follows : Frons without cruciate interf rental 

 bristles ; each orbit with from 3 to 5 bristles, only the upper 

 one directed backward, and no forwardly directed bristles in 

 any species ; thorax normally with but one well-developed pair 

 of presutural dorso-central bristles or, if there are two pairs, 

 the hind tibia has only three bristles, one anteroventral, one 

 anterodorsal, and one posterodorsal. and the fifth sternite is 

 cleft to near base ; lower stigmatal bristle usually directed 

 downward, sometimes weak or absent, in a few species directed 



slightly upward. 



KEY TO GENERA. 



1. Lower calyptra much larger than the upper, projecting beyond it about 



as far as length of upper 2 



Lower calyptra not much larger than upper, projecting but little 

 beyond it 9 



2. Thorax with two pairs of postsutural dorsocentrals ; hind tibia with 



4 median bristles, posteroventral, posterodorsal, anterodorsal, and 

 anterior ; basal segment of hind tarsus with a long bristle near base 



on ventral surface Bithoracochaeta Stein 



-Thorax with three pairs of postsutural dorsocentral bristles ; hind 



tibia with at most three median bristles 3 



.3. Thorax with two pairs of presutural dorsocentral bristles, 



Macrorchis Rondani 



-Thorax with one pair of presutural dorsocentral bristles 4 



-Thorax with the presutural dorsocentrals very short, barely distin- 

 guishable from the dorsal setulose hairs ; fore femur without a 

 continuous series of bristles on posteroventral surface, 



Atherigona Rondani 

 4. Costa discontinued at or slightly beyond apex of third wing-vein, 



Allognotha Pokorny 



