46 NORTH AMERICAN DIPTERA. 



3. All the posterior veins arise from the discal cell, the fifth posterior cell 



hence contiguous with the discal cell 4 



The last posterior vein arises from the second basal cell. . . 5 



4. Third joint of the antennae with a long, delicately fringed, lamelliform 



style ; usually large, more or less elongated species ; males dichoptic 

 (Hermetiinse). . . ... . HERMETIA Latreille. 



Third antennal joint not with such a style ; abdomen short. 



CLITELLAKIN^E. 



5. Antennae with a slender dorsal or terminal, bare or pubescent arista. 



SARGIN^E. 

 Antennae never with a slender or long arista. . . STRATIOMYIN^:. 



BERIDISLE. 



1. Three posterior veins, all arising from the discal cell.* . . 2 

 Four posterior veins, all arising from the discal cell; scutellum with 



spines. 6 



2. Scutellum without spines 3 



Scutellum with spines 4 



3. Short, small species. .... ALLOGNOSTA Osten Sacken. 

 Elongate, larger species ; head sometimes small. (Central and South 



America) CHIROMYZA Weidemann. 



4. Scutellum with ten spines (Central and South America). 



HETERACANTHA Schiner. 

 Scutellum with not more than six spines 5 



5. Head hemispherical BERIS Latreille. 



Head not hemispherical, the front much flattened and elongate (Central 



America). BERISMTJA Giglio-Tos. 



6. Occiput flattened ; hind femora simple ; the last two abdominal seg- 



ments small SCOLIOPELTA Williston. 



Occiput excavated ; hind femora thickened at the extremity. 



NEOEXAIRETA Osten Sacken. 



SAKGIN^E. 



1. Antennae elongate, with a terminal, pubescent style (Central and South 



America) ACROCH/ETA Wiedemann. 



Antennae short with an apical or preapical arista 2 



2. Scutellum with two spines (Central and South America).! 



RHAFHIOCERA Wiedemann- 

 Scutellum without spines. . . . . . . - . . 3 



* Variable in Beris. 



t If but a single submarginal cell present, compare Nothomyia (Stra- 

 tiomyinae?). 



