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UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



Number. The number of eggs which are laid by this insect, so far 

 as we have been able to find, has not been previously recorded. It 

 has been stated approximately as one hundred, and this, so far as our 

 experiments went this year, is not very far from correct. We were able 

 to make individual records of a number of hoppers, and found that the 



Fig. 10. Experimental vine used in the laboratory for obtaining data on the 

 life-history of the hopper. Cages used for confining the insects are 

 shown on the leaves. 



number laid varied from forty to one hundred and twenty-one. These 

 were under laboratory conditions, but not very different from that of 

 the vineyard. The hoppers were confined in cages attached to the grow- 

 ing leaves, as indicated in figure 10. 



These cages were made by cutting a square or rectangular opening 

 in a piece of cardboard, on the underside of which velvet was glued 

 with pile side outward. This rested on the surface of the leaf and on 



