49 



Cluster 4. 



Unfertilized eggs, . . 5 \ 



Eggs with dead embryos, . 21 1 = 18-31 Pr cent., or about 18 per cent. 



Eggs apparently alive, . .116 =81.69 per cent., or about 82 per cent. 



Total, .... 142 



Cluster 5. 



Unfertilized eggs, ^ . 8 J b 



Eggs with dead embryos, . 66 j 



Eggs apparently alive, . .115 =60.85 per cent., or about 61 per cent. 



Total, . . . .189 eggs. 

 The average of these 5 clusters gives the following result : 



Dead eggs, . . . 27 =21.26 per cent., or about 21 per cent. 



Eggs apparently alive, . . 100 =78.74 per cent., or about 79 per cent. 



Total, .... 127 eggs. 



Since this place, in which Flacherie had worked, contained only 100 

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

 than 4 clusters were necessary to equal a normal cluster. Thus the 

 number of fresh clusters must be reduced to about 370. The number 

 of apparently living eggs of this locality therefore had decreased, after 

 the wilt had operated, to about 18 per cent. 



Hingham, Mass. 



Division Agent, F. A. BATES; Local Superintendent, A. W. YOUNG. 



For the experiment an island of about 1 acre was selected, very 

 densely overgrown with low wood. This island is situated east of 

 Water Street and south of the railroad track in the so-called Millpond. 

 The wood consists mainly of oaks and birches of five to six years of 

 age, and of underbrush. The gypsy moth was quite numerous here 

 in the summer of 1909, but there was no disease among the caterpillars, 

 according to the statements of the division agent and the local super- 

 intendent. Several of the clusters were killed with creosote during the 

 winter of 1909-10. The number of the clusters which still remained 

 was estimated by Mr. Young and myself to be about 100. 



The breeding of a series of caterpillars was accomplished exactly 

 according to my instructions by the local superintendent, but unfor- 

 tunately he omitted to send word when the wilt made its appearance, 

 since he had understood that he was to notify me only after all the 

 caterpillars of the brood had died. To convince myself about the con- 



