INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



255 



or dying. Eucalyptus logs cut for lumber are sometimes riddled with 

 burrows made by them. 189 



Food Plants.— During the spring of 1914 both R. S. Vaile and 

 R. K. Bishop observed quite extensive attacks to the smaller branches 

 of the English walnut trees. Coast live oak (Quercus agrifolia), wal- 



Fig. 245. — The nautical borer, Xylotrechus nauticus Mann. Larvae, pupae and 

 adult. Enlarged one and one third times. (Original) 



nut and Eucalyptus globulus are recorded as hosts by Dr. P. E. Blais- 

 dell. 169 To these hosts Dr. Van Dyke adds the peach and the author 

 the black oak. It also attacks madrone. 



Control. — Though common, the beetle has not been very serious in 

 walnut orchards, but should it become so, the destruction of dead trees 

 and logs, where breeding may continue, and the cutting out of infested 

 twigs in the spring will probably prove sufficient to lessen serious 

 injury. 



CHRYSOMELIM: (Family) 



LEAF-BEETLES OR CHRYSOMELIDS. 



The members of this family are known as leaf -beetles because the 

 larvae and adults feed upon the leaves of plants, and chrysomelids 

 because of the small size and beautiful golden colors of some of the 

 species. The tarsi are four-jointed, the antenna 3 moderately long and 

 the legs rather short. Many of the members have the hind femora 

 greatly enlarged for jumping and are known as flea-beetles. A large 

 number of species are injurious, though all feed on plants. There art' 

 many representatives in the State. 



THE CALIFORNIA GRAPE ROOT-WORM 



Bromius obscurus (Linnaeus) 

 [Adoxus obscurus (Linnaeus)] 

 (Chrysomela obscura Linnaeus) 



(Figs. 246, 247) 



Description.— The beetles are jet black or brown, 160 partially cov- 

 ered with fine whitish hairs, giving them a grayish cast, and i\- inch 

 long. The head and prothorax are noticeably narrower than the rest 



""Insect Life, V, pp. 33-34, 1892; Vol. IV, p. 262, 1891. 



""The light-colored form has the wing covers, tibiae and basal half of the antennae 

 brown, the rest of the body, black. Though only a color variation oi the black form, 

 it has been known ;is a separate species, Adoxus vitis Fourc. 



