220 Mr. A. H. Haliday on the generic distribution 



AreolcE pobrachialis et analis perparvcBy modo nan semper 

 incompletoi'^. 



Antennas breves^ articulo 1"*° inconspicuo. 



Arista quasi exarticulata, non nisi dorso pectinata. 



Fades convexa, absque foveolis im,embranaceis. Peristoma 

 rotundatum. Mentum breve incrassatum, Tibice antica^ 

 et posticce setis lateralibus expertes. Ovidepositorium 

 femince plane reconditum t. 



Fallen in his ^Diptera Sueciae^ has divided this tribe into 

 four genera, exclusive of Hydromyza. This number has 

 been greatly multiplied by authors. All the genera added by 

 Meigen appear to represent natural groups, but others equal- 

 ly distinct remain confounded among the numerous Notiphilce 

 and EphydrcE. I have therefore retained the groups proposed 

 by him as well as by Desvoidy, adding a few which seem to 

 be denoted by characters of equal importance. I have not 

 thought it necessary to give all these the rank of genera, but 

 have reverted to the limited number employed by Fallen, 

 One of his [Psilopa) has been degraded, as not materially dif- 

 fering from Notiphila. On the other hand, I have adopted 

 the genus Hydrellia of Desvoidy, comprehending with it two 

 allied groups unnoticed by him. I have not had occasion to 

 refer much to Macquart ; as his arrangement, where it departs 

 from those before named, does not seem to be improved in 

 consequence. It is rarely that this can be objected to any 

 portion of his classical work. For the determination of the 

 species, nere as elsewhere, the Diptera of Europe by Meigen is 

 the standard of reference. Macquart has added some to the 

 number, and Desvoidy has described several Notipfdlce, Hy- 

 drellicB and Hydrynce, apparently unnoticed by either, 



Generum Synopsis. 

 Femora antica. 



{ovata incrassata, 1. Oclithera. 

 subaequalia ; 



• For an exception see Ephydra nasica. The imperfection of the same 

 areolets is a character of the OscinidcE also ; but in that tribe they become 

 incomplete after attaining their full development in the Loxoceridce. This 

 appears as well from the indication of their limit in the thickening of the 

 nervures and the corresponding divarication of the radial and cubital nerves, 

 as from the analogy of the last named tribe. 



f There is a slight exception in the subgenera Glenanihe and Te'idio- 

 myza. 



