THE OLIVE INSECTS OF CALIFORNIA 



55 



the adults resemble very closely the fruit-tree bark-beetle, Eccopto- 

 gaster rugulosus (Ratz.), a common pest to deciduous fruit trees in 

 various parts of the state. The work also resembles that of this 

 beetle and consists in the destruction of tke cambium layer by numer- 

 ous small burrows (fig. 8) which may entirely girdle the infested 

 portions of the trees. The perfectly round entrance and exit 



f\ D E 



Fig. 9. The olive bark-beetle, Luperisinus calif ornicus Swaine. A, adult; B and 

 C, leg and tarsi; D, plumose hairs from body; E, antenna. Enlarged. (Original.) 



holes of the adults through the bark are the only distinct external 

 evidences of the work, excepting the general unhealthy appearance 

 of the infested trees. The insects apparently prefer sickly or dying 

 trees and breed abundantly in them as well as in the dead prunings. 

 However, like many of the orchard bark-beetles, they will not hesitate 

 to attack perfectly vigorous and sound trees in close proximity 

 to their breeding places, especially if an entrance may be gained 

 through a sunburned or wounded spot. 



The distribution of the species is not well known. Besides the 

 infestation in San Diego County, already referred to, adults were 

 taken at Camp Greely, Fresno County, as early as 1909 by Mr. Ralph 

 Hopping, 4 but no host plants were recorded, the specimens having 



* Canadian Entomologist, vol. XLVIII, no. 6, p. 192, June, 1916. 



