10 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



of the dorsal line, and below these laterally is a similar single spine. 



There are also hairs or bristles extending farther laterally. 



The Beetle. There 

 are two forms of 

 the adult beetle oc- 

 curring in the State, 

 one being black in 

 color and the other 

 mostly brown. 

 There is consider- 

 able difference in 

 the size of different 

 specimens, and par- 

 ticularly in the 

 sexes the males 

 being much smaller. 

 On an average they 

 will measure about 

 one fifth of an inch 

 in length. 



The black form 



FIG. 5. Pupa. Ventral view. (AdoxUS 



Linn.) is almost 

 wholly black in color. 

 The antennas, tibia 

 and tarsi, however, 

 in some specimens 

 merge into dark 

 brown. The entire 

 body, as well as the 

 appendages, are cov- 

 ered with a pubes- 

 cence 'of short gray 

 hairs. 



The brown form 

 (Adoxus vitis Fab.) 

 has the elytra, tibia 

 and basal half of 

 the antennae brown, 

 while the remaining 

 parts are black. It 

 is covered " with a 



FIG. 6. Adult of the grape root- worm. 



gray pubescence as is the other form. The head in both is capable of 

 being well retracted into the prothorax. Both forms of the beetle are 

 about equally distributed, and interbred indiscriminately. 



