36 DIPTERA OF NORTH AMERICA. 



Fam. XXXVII. ANTHOMYIDAE. 



Charact. Thorax with, a complete transverse suture. Fourth longitudi- 

 nal vein straight or nearly so, hence first posterior cell fully open. 

 Tegulaj rather well developed, though in many cases of no large 

 size. 

 The riches of the X. A. Fauna in this family have been very 

 little explored. I know species of the following genera only: 

 Anthomyia Meig., Homalomyia Bouch., Hylemyia Macq., Ari- 

 cia Rob. Desv., Lispe Latr., and Cosnosia Meig. The notices of 

 Mr. Walker about the occurrence of some species of Eriphia and 

 of one Dialyta appear to me very uncertain. 



Fam. XXXVIII. CORDYLURIDAE. 



Charact. — Neuration of the wings complete ; both posterior basal cells of 

 considerable size ; auxiliary vein well separated from the first lon- 

 gitudinal vein ; first longitudinal vein bare. Whole lateral border 

 of the front bristly; anterior border of the mouth with strong, 

 usually numerous vibrissa. Tibiae with spurs. 



With the Cordyluridse we begin that division of Diptera which 

 is called acalyptratee, and the systematical arrangement of which 

 is still and will be an unsolved problem, till their structure has 

 been much more thoroughly studied than has been hitherto the 

 case. In the present state of our knowledge their subdivision into 

 a greater number of families seems to be the most advisable course 

 to pursue. 



As for their exterior, the Cordyluridse mostly approach to the 

 Anlhomyidse, and namely to the species of the genus Coenosia, but 

 the smaller size of their tegulse and the less incomplete develop- 

 ment of the transverse suture on their thorax serve to distinguish 

 them. On the other side they are closely allied to the Helomyzidse, 

 in which, however, the front bears bristles on its upper half only, 

 the two posterior basal cells are smaller, and the costa of the wings 

 is always bristly. 



N. A. possesses species of Cordylura, some of them very inter- 

 esting, and a number of Scatophagy among which several coin- 

 cide with European species. 



