8 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



control for such a root infesting insect. In the same bulletin it is 

 stated that some large vines of a ' ' native type ' ' growing along a fence 

 within a few feet of a badly infested Concord vineyard suffered no 

 injury, not even the leaves being eaten by the beetles. 



Our own observations on the matter of resistant varieties for the root- 

 worm in California have not been extensive enough to warrant drawing 

 any conclusions. The infested vineyards at Lodi are of tlje Tokay and 

 Zinfandel varieties, but since these are the principal grapes grown 

 here, it proves nothing. In other sections many different varieties of 

 vines are subject to attacks by this insect. 



APPEARANCE AND DESCRIPTION OF THE STAGES. 



The Egg. The eggs of this beetle are small yellowish white objects 



FIG. 1. A cluster of eggs as they are found naturally on the 

 bark (enlarged). 



FIG. 2. 



A single egg highly 

 magnified. 



which may be found in clusters (Fig. 1) under the old bark of the vine. 

 An individual egg (Fig. 2) is about one twenty-fifth of an inch long 

 and somewhat cylindrical in shape, being about one third as broad as 

 long. 



The Larva. The full grown larvae vary considerably in size, but 

 the larger number will measure a little more than a quarter of an inch, 

 as they are found naturally in a slightly curved position. When they 

 are straightened out they measure seven twentieths to eight twentieths 

 of an inch. They are white in color, excepting the head, which is yellow- 

 ish brown,, with the mouth parts dark brown or black. The arrangement 

 of hairs is as shown in figure 3. The spiracles are indicated by a yellow- 



