332 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



normal, injured and dying trees; white alder {Abins rhombifolia) and 

 mountain alder {A. tenuifoUa) ; flies from April to July; feeds on foliage 

 of host plant; lays its eggs in masses of from one to twelve on the smooth 

 bark of branches and trunk; girdles and kills branches and trunk; life 

 cycle seems to be one year ; very destructive to the white alder in some 

 parts of California; when an attack does not kill the tree it causes 

 rough scars on the trunk and swollen galls on the branches; appears 

 to be the only species that attacks the alder in California. 



From an economic standpoint the two main points brought out by 

 the preceding observations are: first, that the adults of some of the 

 most injurious species feed on the foliage of the host plant where they 

 may be fought with poison sprays; second, that they lay their eggs 

 upon tiie bark where they may be reached by contact sprays. 



Up to the present time the general methods of control recommended 

 for flathead borers have been the cutting out and burning of the in- 

 fested parts or the protection of the plant by repellent washes or 

 protective coverings. These methods when carefully applied are very 

 effective and will continue to be important but along with them the 

 measures suggested in the preceding paragraph have their place and 

 in many cases their prompt use ought to make the severer measures 

 unnecessary. 



Take, for instance, Agrilus politus which causes severe damage to 

 the alder and willow often killing many trees in a group. The adults 

 feed on the leaves and then lay their eggs on the smooth bark of the 

 limbs and main trunk. An arsenic spray on the foliage should kill 

 the adults and any of the oil or sulphur sprays should destroy the eggs 

 on the bark. And the result should be the same in the case of Chrij- 

 sohothris mali which is a destructive enemy of shade and fruit trees. 



The main point in the use of any of these measures is careful observa- 

 tion to determine the amount of damage the insect is doing, the exact 

 time when the control work should be done, that the proper method is 

 selected to suit the particular conditions found and that the method 

 used is properly applied. The most perfect remedy will not bring the 

 best results unless it is used in the right place at the right time. 



Chairman A. W. Morrill: As it is now lunch time we had 

 better adjourn until 2 p. m. as announced on the program. 



Adjourned 



After a very fine luncheon provided by the members of Stanford 

 University for all members of visiting societies the meeting was called 

 to order at 2 p. m. by Chairman A. W. Morrill. 



Chairman A. W. Morrill: The first paper for this afternoon will 

 be read by Dr. H. H. P. Severin. 



