THE MONTHLY BULLETIN. 589 



Work. 



The work of the beetle is very characteristic consisting of clean round 

 burrows in the branches extending into the pith or even through to 

 the other side. These burrows are usually from one eighth to one 

 fourth of an inch in diameter and scarcely more than one inch in 

 length. In making these the beetles begin in the axil of a bud or small 

 branch and bore downward. It is not at all difficult to find them doing 



this. 



Appearance and Life History. 



The adult beetles are shown in Fig. 339. They vary considerably in 

 size and are usually from three to five eighths of an inch long. They 

 are narrow, the head as wide or slightly wider than the prothorax. 

 The color varies from light to very dark brown and the entire body is 

 covered with short, fine hairs, which are noticeably thick on the head 

 and prothorax. The movements are very slow and deliberate. 



The life history of the beetle is very imperfectly known. In 1881, 

 Matthew Cooke^ recorded it as a pest in California. He supposed that 

 the eggs were deposited in forest trees within which the larvas sub- 

 sequently lived. This belief was practically substantiated by the work 

 of Dr. F. E. Blaisdell,^ who reared adults from larvae in live oak and 

 almond trees. The writer has been unable to find other records of 

 the young attacking orchard trees. 



In all the instances noticed the adults are doing the damage. They 

 work in the spring and early summer, disappearing as suddenly as 



they came. 



Control. 



At the present there is no known means of preventing the attacks of 

 this borer. The only remedies suggested are to cut and burn the 

 infested twigs and to destroy the beetles in the burrows by means of a 

 short wire or knife blade. Both of these are tedious and require con- 

 stant vigilance to be effective. 



Distribution. 



Matthew Cooke records this insect from Solano and Sonoma counties. 

 Dr. Blaisdell collected it in Calaveras County. The writer has received 

 it from, or collected it in, the following counties: El Dorado, Napa, 

 Riverside, Sacramento, Tehama. Ventura and Yolo. To these Prof. 

 Woodworth adds Mendocino. Santa Cruz, Santa Clara, Contra Costa, 

 Alameda, San Joaquin and Butte. 



From the above it will be seen that it is generally distributed through- 

 out the State. 



Food Plants. 



The list of plants attacked by the branch and twig borer is already 

 large and is likely to increase with the amount of orchard inspection. 

 Those alreadv known are : almond, apple, apricot, cherry, currant, fig, 

 grape, live oak, olive, orange, peach and pear. The native host appears 

 to be the live oak. 



=Iniurious Insets of the Orchard, Vineyard, etc., 1SS.1, p. 116. 

 ^Insect Life, Vol. V, p. 34. 



