314 INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



Distribution. — The beetle occurs along the central coast in the 

 counties adjacent to San Francisco Bay. 



Food Plant. — The Lawson's cypress seems to be the preferred host 

 and soon succumbs to the attacks of the beetle. The deodara cedar is also 

 sometimes seriously injured. 



Control.— The elimination of all infested trees and their destruction 

 by fire is desirable to save those not yet attacked. During the winter 

 months, when the beetle is in the larval stage, is the best time to do this. 

 The presence of the beetle is easiest to ascertain in March and April, 

 when the adults are emerging and reentering, as there are many holes 

 made at that time. 



THE LESSER SHOT-HOLE BORER 



Xyleboms xylographus Say (Family Ipidse) 



[Xylcborus saxeseni (Ratzeburg) ] 



(Figs. 309, 310) 



Description. — The adults are very small, nearly cylindrical, dark 

 brown or black beetles, about T V inch long and 1-35 inch wide. The 

 head is situated directly under the prothorax, 

 which is nearly half as long as the entire body 

 (Pig. 309). 



Life History. — The larvie spend the winter 

 within their burrows and pupate early in the 

 spring, so that adults begin to issue in March and 

 April. These burrow into the heartwood of trees 

 and deposit eggs in the tunnels. The eggs hatch 

 into very small white or yellowish grubs, which 

 Fi g 309 The lesser work within the trees during the summer and 



shot-hole borer, Xyle- winter. 

 bonis xylographus Say. 



umes ts '(Ori la in Se n six Nature of Work. — The burrows made by the 

 beetle are plainly shown in Fig. 310. They pene- 

 trate into the heartwood of the trees and the waste material is forced 

 out of the burrows, like tiny piles of sawdust around the mouth. Trees 

 become so riddled with the many tunnels that they are reduced to a 

 mass of fine wood dust. While the beetles normally attack only dead 

 or unhealthy trees, they are often responsible for killing trees which 

 might not otherwise die. They may begin their attacks in an unhealthy 

 spot and extend their work to perfectly sound portions. 



Distribution. — The species is widely distributed throughout this 

 State and the Pacific slope. 



Food Plants.— Records in our office show this beetle to have been 

 reared from apricot, prune, plum, cherry, lemon and orange trees. To 

 this list Dr. Van Dyke adds the following: apple, beech, larch, pine, 

 hickory, pear, oak, maple, hemlock and spruce. 



Control.— The control of this pest is practically the same as recom- 

 mended lor the shot-hole borer or fruit-tree bark-beetle, Eccoptogaster 

 rugulosus. 



