18 DIPTERA OF NORTH AMERICA. [PART III. 



having succeeded yet, howevei', in identifying the species, I am 

 not positive about it. 



The genus Delphinia is established for Trypeta picta, Fab., 

 which Rob. Desvoidy did not recognize; the unbecoming generic 

 name was afterwards replaced by Camptoneura Macq. 



The genus Acidia belongs to the Trypetidse. 



Myrmecomya (more correctly Myrmecomyia) and Polystodes 

 (better Polistoides) taken together nearly correspond to the 

 genus 3Tichogaster (better Mischogaster) of Macquart, placed 

 by the latter among the Sepsidse. The size of the palpi and 

 the structure of the ovipositor do not justify this location, and 

 the genus undoubtedly belongs to the Ortalidse. 



Of the position of the genus Stylophora in the system I. 

 cannot judge, not knowing the species upon which it is based. 



Herina (the derivation of the name is not apparent) com- 

 prises species from the relationship of Ortalis pallidum. 



The genus Myodina (again a name of obscure derivation) is 

 based upon Ortalis vibrans, which R. Desvoidy took for Ortalis 

 urticse. Macquart, in the Suites a Buffon, very erroneously 

 united this genus with Ortalis, throwing together various very 

 different species. Long before Rob. Desvoidy, Kirby had used 

 for Ortalis vibrans the generic name of Seioptera. 



Richardia is founded either upon Dacus podagricus Fab., not 

 recognized by Rob. Desvoidy, or else on some closely allied 

 species. 



Rivellia (probably a dedication name) contains species re- 

 lated to Ortalis syngenesise, and among them this very species, as 

 usual, not recognized by Rob. Desvoidy. Macquart in the Suites 

 a Buffon unites Rivellia with Herina, while the species really 

 belonging to it are put in the genus Urophora, or even in Pla- 

 tystoma; and upon one of them, in his later works, he even es- 

 tablishes a new genus, Epidesma. 



Whether the genus Boisduvalia really differs from the pre- 

 ceding only in the length of the third antennal joint seems very 

 doubtful ; should this be the case, the separation of these two 

 genera would not be justified. 



Clidonia is considered by the author himself as belonging to 

 quite a different family, in which we will not contradict him. 



Setellia seems to contain Ortalidse resembling Micropezidae in 

 their general appearance. 



