REPORT ON CALIFORNIA INSECTS. 



By Albert Koebele, Special Agent. 



LETTER OF TRANSMITTAL. 



Alameda, Cal. October 25, 1889. 

 Sir : I herewith submit my report upon observations made and work done since 

 my return from Australia. 



After returning to Alameda on April 15, some time was taken up in writing out 

 my reports upon work done in Australia, and also in assisting in raising and distrib- 

 uting in the northern part of this State the Australian Ladybird-enemy of the Icerya. 

 This Ladybird does remarkably good and speedy work everywhere. As usual my chief 

 work has been the breeding and studying of all insects, injurious and otherwise, that 

 have come under my notice, the special notes on which will accompany material that 

 will be sent in. 



Respectfully, 



Albert Koebele. 

 Prof. C. V. Riley, 



U. S. Entomologist. 



THE MADRONA TREE BORER. 



(Polyeaon confertus Lee.) 



This destructive beetle occurs to a greater or-less extent every spring; 

 and summer upon various fruit-trees, vines, etc., boring into the fresh 

 wood and destroying it. During my stay in the Santa Cruz Mountains 

 the past summer they were observed everywhere, and most abuudantly 

 during May and June. On any dead tree, as soon as the leaves begin 

 to fade, this beetle may be found, though always most abundantly upon 

 the Madrona tree (Arbutus menziesii). Old trees of this species, such as 

 have been allowed to lay on the ground for a year or two, are always 

 completely perforated with holes from which these beetles have made 

 their exit. In cutting through, one finds the wood nothing but mines 

 produced by the larvae, the mines generally running lengthwise, but often 

 crossing each other. The Madrona tree seems to be the ordinary if not 

 the only plant in which the beetle breeds. Notwithstanding that the 

 mature insect bores in almost any kind of fresh wood, and especially 

 favors such as has been somewhat injured by the hot sun, the larva is 



85 



