198 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



The Varieties of the Species Comes. Altogether there are nine 

 varieties of this species recognized in the United States. 1 All the 

 specimens taken on the grape this year about Lodi and Fresno, Cali- 

 fornia, were the typical comes, and the variety coloradensis. The 

 difference between these two varieties is that coloradensis has a black 

 spot on either side of the scutellum at the base, while in comes these 



Fig. 13. A vine enclosed by a cheese-cloth cage, open at the top, for 

 studying migrations. 



spots are wanting. Comes largely predominates, as is indicated by 

 the following table. The specimens were mounted on velvet between 

 two miscroscope slides, and collected on the dates given: 



Proportion of the Varieties of the Grape Leaf-hopper. 



1 Gillette, Proc. U. S. N. M., vol. 20, 1898, p. 709. 



