4 BULLETIX lOSO, U. S..DEPARTMEXT OF AGRICULTURE. 



of 1915-16. Ten clusters were collected at each -point on the first of 

 each month, beginning in September and ending in April. Subse- 

 quently they were handled exactly as descriljed. 



As the sets of weather instruments vrere located at three of the 

 collection points, the records obtained from these are the most valu- 

 able. The other three, however, were kept as collection points for 

 purposes of comparison. 



MONTH'S EXPOSURE. 



As controls on the naturally produced egg clusters obtained in 

 " monthh" collections," a series of experiments were conducted with 

 clusters produced at the laboratorj". To obtain these, vigorous males 

 and females were mated in a small cage, and later the females were 

 confined in small tin boxes, where they deposited their eggs upon 

 pieces of thin wood. 



Ten such clusters were tacked to trees at each point where there 

 were weather instruments and allowed to remain in the open just 

 one month. The first set was out from September 1 to October 1, 

 the second from October 1 to Xovember 1, and so on. The last set 

 placed out April 1 was brought in just before hatching time. After 

 exposure the clusters were handled as in all the other experiments. 



NATURAL PROTECTION. 



Kotes taken in connection with the " observation-point " investiga- 

 tions showed that in certain localities there was considerable differ- 

 ence in hatching on different parts of the trees. Clusters found un- 

 der roots or in cavities close to the ground, as well as those fully 

 exposed close to the ground, appeared to hatch completely, while 

 those higher up failed to do so. 



Investigation at a number of chronic nonhatch points proved that 

 in general it would be rather difficult to find enough clusters naturally 

 deposited where they were wanted. Therefore, at each of the six 

 points from which monthly collections were obtained 100 new clusters 

 were cut from the trees and tacked back in the following positions : 



Twenty-five clusters were tacked under roots or in cavities close 

 to the ground. Usually these. were covered with leaves. 



Twenty-five at the base of a tree close to the ground but entirely in 

 the open. 



Twenty-five on the trunk well up from the ground, usually about 



5 feet. 



The remaining 25 were brought in to serve as controls. 

 Collection of these clusters was made just before hatching time 

 each spring. 



ARTIFICIAL PROTECTION. 



Originally these experiments were planned when the fungus found 

 in the nonhatch eggs was looked upon as a possible cause. Various 

 means were tried of protecting the clusters against infection, but 

 most of these were abandoned when the true nature of the fungus 

 became apparent. 



Two experiments in artificial protection were continued. The 

 first, by means of a wire cage suspended between trees, sought to 

 protect the clusters contained therein from any influence the tree 



