BUEEAU CF ENTOMOLOGY. 259 



ened outbreak in order to prevent the great loss of timber which 

 would occur before natural control became operative. 



Another special study was made of the number of all staa<.>s of 

 the Avestcrn pine beetle in 830 square feet of infested bark selected 

 from G7 trees, which represented an average infestation within an 

 area of approximately 3G square miles. It was shown that there is 

 a large percentage of mortality between the young and matured 

 stages^ in the developing broods, but that normally an average of 

 about 150 beetles to the s(]uare foot of bark developed to the adult, or 

 reproductive, stage; which would be 50,000 beetles to the average in- 

 fested tree, or, say, 39,000 beetles to 1,000 board feet of timber. Sinc;^ 

 it requires an average of about 10 beetles to the square foot to attac': 

 and kill a vigorous, healthy tree, it will be seen that all the pin> 

 timber of the western forests would soon be destroyed were it not for 

 natural and artificial control. 



Experiiiients to determine the time of year to cut and the method 5 

 of handling mesquite for fuel, posts, etc., to avoid destruction by 

 wood-boring insects, have been nearly completed, and the results 

 show that serious loss in the Southwest can be prevented by cuttin;;- 

 the trees in the late fall and early winter and piling the wood i-i 

 loose piles until it is thoroughly dry. Damage to posts can be pre- 

 vented by cutting them at any dme and laying them on the ground 

 where tliey Avill receive the fiill force of the su]i, turning them occii- 

 sionally so that tlie young stages of the borers will be killed by thu 

 heat. 



Studies of damage to lead telephone cables in California by a 

 wood-boring beetle have been continued, and the results so far shov/ 

 tliat the beetle is able to penetrate alloyed substances that are con- 

 siderably harder than lead. The problem is still unsolved, and it 

 will be difficult to find a practical means of controlling this pest, 

 which is able to put hundreds of telephones out of commission by 

 boring holes in the cables, through which the water enters, renderiu'V 

 the w'irc connections useless until the place is found and repaired. 



EASTERX WORK. 



Continued experiments with chemical substances applied to fin- 

 ished and crude forest products show that very few of the many 

 substances that have been tried are effective, and, with crude products, 

 none of them are so economical as simple and inexpensive manage- 

 ment in logging and manufacture which will render the conditions 

 of the barirand'the wood unfavorable to attack. 



Continued studies of termite, or white ant, damage to the wood- 

 work of buildings has led to the discovery that one of the most 

 destructive species can not live if deprived of moisture in ground 

 or foundation timbers ; thus it is possible to prevent serious damage. 



Investigations of shade-tree insects have continued, and there has 

 lieen much correspondence about insects of this class. 



The recent appearance of the so-called seventeen-year locust, or 

 periodical -cicada, has given an opportunity for detailed study oi 

 certain points, and motion pictures have been made. 



STUDIES OF THE BIOCLIMATIC LAW. 



A law of latitude, longitude, and altitude as a guide to practice i:i 

 fighting insects, and of value in the practice of agriculture, was first 



