2 Journal New York Entomological Society. [VoI. xviii. 



basin near Florissant, Colorado, and from these many genera have 

 been taken which have been lately described (Cockerell, '06, and 

 Brues '06, '10). These two sources taken together have already 

 afforded such a considerable number of types that it is now possible 

 to draw from the accumulated data some general conclusions regard- 

 ing the phylogeny and geological history of certain components of 

 this most interesting series of insects. Although necessarily quite 

 incomplete and of a tentative nature, these have a bearing on the 

 relationship of recent faunae and are of both theoretical and practical 

 interest, more particularly in view of the recent great advances made 

 in the utilization of parasitic insects in combating injurious species. 

 The following list, compiled both from the literature and from 

 unpublished observations, includes all the accurate determinations 

 of genera relating to the parasitic Hymenoptera of Baltic amber and 

 of the Miocene shales of Florissant. To facilitate a comparison of 

 the two fauns, they have been placed in parallel columns, with the 

 corresponding families in juxtaposition. 



Genera Occurring in Baltic Amber and at Florissant.* 



Baltic Amber. 



Sierola. 



Parasierola. 



Epyris. 



Bethylincv gen. nov. 



Dryinus. 



Chelogynus. 



Dryinince gen. nov. 



Proctotrypes. 



Several genera. 



One genus. 



Bethylid^. 



Proctotrypid^. 



Belytid.e. 



Diapriid^. 



Florissant Shales. 



Epyris. 



Proctotrypes. 



Pantocilis. 

 Belyta. 



%Galesimorpha. 



* Names preceded by an asterisk (*) have been previously found by 



other observers, those preceded by a dagger (f) have not been seen fossil by 



the writer and those preceded by a double dagger (t) are those of extinct 

 genera. 



