SOUTH AMERICAN DIPTERA. 265 



20. ITIesograpta aiichorata Maccx. 

 Chapada, several specimens. 



21. jVIesograpta niii»$ieus Wied. 

 One specimen, Corumba. 



22. iflesograpta sp. 



Not unlike M. insignh Schiner, but the anterior black dilatation 

 of the third and fourth abdominal segments projects each side more 

 acutely, and does not have the small, oval, lateral spot ; the face is 

 more or less blackish in the middle, the antennje brownish or black- 

 ish above, the scutellum black with a yellow margin, and the hind 

 tibiie and tarsi brownish or blackish. 



Numerous specimens, Chapada. 



23. Mesog^rapta sp. 



There are three or four other species from Rio de Janeiro and 

 Chapada that I am unable to determine. 



24. Ocyptaiiius diinidiatns Fabr. 

 Numerous specimens, Chapada, Rio de Janeiro. 



25. OcyptainuN trigoniis Wied. 



Bacclui torva Williston, Synopsis N. A. Syrphidge, 124.— Texas. 



Forty specimens, Chapada. The description of B. torva applies 

 better than does Wiedemann's, nevertheless, there is no doubt of the 

 determination. 



26. Ocyptaiiiii»« tiiiiebris Macq. 



Ten specimens, Chapada, Rio de Janeiro. 



BACXHA. 



TABLE OF SPECIES. 



1. AliiliP rudimentary; mesonotuiu sliinint; hiack with slender pollinosestripe.s, 



yellow on the sides o. 



Alulae not rudimentary 5 



2. Very slender species ; ahdonien as long, or lonjrer than the wings .3. 



Less slender : abdomen shorter than the winjrs; face yellow J. 



.3. Front below finely rugose !>>teiiogasfer n. sji. 



Front not rugose below varie^ata. 



4. Wings hyaline, with the subcostal cell and a spot in the end of subinarginal 

 hrowu exigiia n. sp. 



Wings uniformly tinged with yellowish brown sp. 



TRANS. AMER. KNT. SOC. XV. (34) NOVEMBER, 1888. 



