51 



Cluster 5. 



Unfertilized eggs, 4 \ 



T-, ' , n > = 9.22 per cent., or about 9 per cent. 



Eggs with dead embryos, . 9 J 



Eggs apparently alive, . . 128 =90.78 per cent., or about 91 per cent. 



Total, . . . .141 eggs. 

 The average of these 5 clusters gives the following result : 



Dead eggs, . . . 11 = 8.09 per cent., or about 8 per cent. 



Eggs apparently alive, . . 125 =91.91 per cent., or about 92 per cent. 



Total, . . . .136 eggs. 



Since this place, in which Flacherie had operated, contained only 125 

 eggs with apparently living embryos on the average per cluster, almost 

 4 clusters were necessary to equal a normal one. The number of the fresh 

 clusters thus must be reduced to about 5. The number of apparently 

 living eggs of this locality therefore had decreased, after the wilt had 

 worked, to about 5 per cent. 



Byfield, Mass. 



On June 30, 1910, a letter was received from Mr. James 0. Hale 

 of Byfield, in which he stated that he had heard of my Flacherie ex- 

 periments of 1909, and asked for aid in diminishing the gypsy moth 

 caterpillars by using Flacherie. I therefore visited the locality on 

 July 5, 1910, and took with me sick and dead caterpillars which had 

 been raised at Forest Hills. The forest in question is about 4 to 5 

 acres in size, and consists mainly of oaks of different ages and some 

 underbrush. It is situated on the border between Rowley and Newbury. 

 It is not isolated, but connected with woods which belong to other 

 persons. At the time of my arrival most of the caterpillars had already 

 undergone the fifth molt, so that it seemed questionable whether the 

 disease would be able to show much success this year. The infected 

 material was exposed in the southwestern part of the forest, about 

 7 feet from the ground. It proved to be impossible to secure a correct 

 estimate of the caterpillars which were present; all that could be stated 

 was that the caterpillars were quite plentiful. 



This locality was visited again with Mr. Hale on Sept. 16, 1910, to 

 determine the results. Mr. Hale gave his opinion that there was, at 

 the least, no increase in the number of egg clusters compared with that 

 of the previous year, although there was no visible decrease in the 

 number of the fresh clusters. However, these fresh clusters were con- 

 siderably smaller than those of the preceding year. 



The first 5 clusters collected gave the following counts : 



