More Hunting Wasps 



tity of the provisions in itself points to the 

 sex: for the females it is twice or thrice as 

 great as for the males. 



In the scantily-provided cells, I double or 

 treble the ration with food taken from other 

 cells; in the cells which are plentifully sup- 

 plied, I reduce the portion to a half or a 

 third. Controls are left: that is to say, 

 some cells remain untouched, with their pro- 

 visions as I found them, both in the part 

 which is abundantly provided and in that 

 which is more meagrely rationed. The two 

 halves of the reed are then restored to their 

 original position and firmly bound with a few 

 turns of wire. We shall see, when the time 

 comes, whether these changes increasing or 

 decreasing the victuals have determined the 

 sex. 



Here is the result: the cells which at first 

 were sparingly provided, but whose supplies 

 were doubled or trebled by my artifice, con- 

 tain males, as foretold by the original amount 

 of victuals. The surplus which I added has 

 not completely disappeared, far from it: the 

 larva has had more than it needed for its 

 evolution as a male; and, being unable to 

 consume the whole of its copious provisions, 

 it has spun its cocoon in the midst of the 

 remaining pollen-dust. These males, so 

 richly supplied, are of handsome but not ex- 

 230 



