TAXONOMY OF MUSCOIDEAN FLIES — TOWNSF.ND 6l 



indicate differences between Phasiopteryx and Neoptera, the signifi- 

 cance of which did not appeal to the writer at the time. It seems 

 quite certain that several forms are confused here. The specimens 

 that the writer has seen of related forms in the CEstrophasiinae in- 

 cline him to the belief that large series of material will demonstrate 

 the distinctness of Neoptera and Phasiopteryx. It must be remem- 

 bered that only a fraction of the neotropical fauna is yet known. 



Besides the differences, pointed out below, between CEstrophasia 

 and Phasiopteryx, the following may also be noted : CEstrophasia 

 and Ccnosoma have the facial plate flat or subcarinate ; antennae in- 

 serted distinctly below middle of extreme head height, almost as 

 low as lower margin of eyes ; arista very short and bare, and third 

 antennal joint only about as long as second. Phasiopteryx has the 

 facial plate more strongly, often quite strongly, carinate ; antennae 

 inserted but little below middle of eyes, distinctly above middle of 

 extreme head height ; arista very long, very distinctly but finely and 

 thinly hairy (looks bare in some specimens, apparently from the fine 

 hairs being lost or rubbed off), and the third antennal joint always 

 twice as long as second. 



Subfamily CEstrophasiix.e 

 Genus CEstrophasia Brauer and von Bergenstamm 



CEstrophasia clausa Brauer and von Bergenstamm. — This is a 

 northern species. The specimens from Cuautla, Mexico, referred 

 here bv Giglio-Tos, doubtless represent another form. Cuautla is 

 thoroughly tropical, and clausa is a transition and boreal form. 



The ultimate section of fourth vein in Cenosoma signifera and 

 calva is normally rather deeply bowed in, but not so in CE. setosa 

 and clausa, both of which have the apical cell very short petiolate, 

 while setosa has third vein bristly nearly to small crossvein. 



The antennae of CEstrophasia and Cenosoma are widely separated 

 by a characteristic median enlargement of the lunula in both sexes 

 of all the species. This is absent in Phasiopteryx, which has the 

 antennae closely approximated. 



Genus Euoestrophasia Townsend 



Eua-strophasia aperta Brauer and von Bergenstamm. — This South 

 American form seems generically distinct from the species of CEs- 

 trophasia in its open first posterior cell, as pointed out in Trans. Am. 

 Ent. Soc. xix (1892), p. 133. 



