CONTENTS. 



Proceedings. 



Notes on Variation in Duration of Similar Periods of Embry- 

 onic Development : Its Bearing on the Theory of 

 Effective Temperatures . . . A. A. Girault 



A Check-List of Wisconsin Mammals N. Hollister 



A Preliminery List of the Flies of Wisconsin, Belonging to 

 Families Bombyliidae, Syrphidae, and Conopidae 



. S. Graenicher 



Notes and Descriptions of North American Parasitic Hymen- 



optera, VIII '. Charles T. Brues 



New Records of Wisconsin Dragonflies . Richard A. Muttkowski 



Actual date of publication, May 7, 1910. 



