JOURNAL 



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Vol. XVIII. MAECH, 1910. No. 1 . 



SOME NOTES ON THE GEOLOGICAL HISTORY OF 

 THE PARASITIC HYMENOPTERA.* 



By Charles T. Brues. 

 Boston, Mass. 



Part I. General Considerations. 



The occurrence in considerable abundance of fossil parasitic 

 Hymenoptera in the deposits of the early and middle Tertiary has 

 long been known, but it is only quite recently that they have received 

 close attention. As early as 1849, in his classical v^ork on the fossil 

 insects of the Radoboj (Lower Miocene) and Geningen (Upper 

 Miocene) deposits, Heer ('47) described a considerable number of 

 species belonging to these families, but this was before the classifi- 

 cation of recent forms had been well worked out, and on this account 

 his results are unsatisfactory from a more modern standpoint. The 

 very rich fauna of Baltic amber (Lower Oligocene) was the subject 

 of a brief note by Brischke ('86) where the occurrence of a number 

 of recent genera in amber was recorded. I have lately had the oppor- 

 tunity to examine a small collection from the same source and have 

 been able to detect a considerable series additional to those seen by 

 Brischke. In America there is a very rich fauna of parasitic 

 Hymenoptera preserved in the Miocene shales of an old Tertiary lake 



* Contributions from the Entomological Laboratory of the Bussey Institu- 

 tion, Harvard University, No. 14. 



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