62 



Psyche 



[April 



THE DIFFERENTIATION OF THE COCOONS OF PELO- 

 PCEUS C^MENTARIUS AND CHALYBION CMRU- 

 LEJJM (HYMEN.). 



By Phil Rau, 

 St. Louis, Missouri. 



A large number of mud-daubers' nests had been gathered for 

 the purpose of a study of the contents of their cells. The nests 

 appeared to be all of the same kind. While opening them, however. 



Fig. 1. 1, Cocoons of Chalybion candeum; 2, Cocoons of Pelopcpus cotmentanus. 



we were for a time puzzled by a variation in the structure of 

 the cocoon. Some of the cocoons were of a rich brown color 

 and of papery consistency, with smooth surface as though glazed 

 (Fig. 2) ; others were of a whitish color and of soft, webby texture 



