27 



Cluster 4. 



Unfertilized eggs, ^ . 3 1 =13 . 38 nt bout 13 . 5 per cent . 



Eggs with dead embryos, . 18 J 



Eggs apparently alive, . .136 =86.62 per cent., or about 86.5 per cent 



Total, . . . .157 eggs. 

 Averaging these 4 clusters we get : 



Dead eggs, . . . 20 == 6.67 per cent., or about 6.5 per cent. 



Eggs apparently alive, . . 280 =93.33 per cent., or about 93.5 per cent. 



Total, . . . .300 eggs. 



Since, as we have seen, a normal cluster contains on the average 

 433 eggs with apparently living embryos, the living eggs of these 4 

 clusters, after the wilt did its work, amount to about 64.5 per cent. 

 The egg clusters which were present in the spring of 1910 were esti- 

 mated at about 25, while only 4 fresh clusters were found in the 

 autumn of 1910. The total number of all apparently living eggs was 

 decreased in this locality to about 13 per cent., as compared with the 

 number present in the spring of 1910. 



Another place for experiments, very similar to the last one, was 

 selected in North Carver. This is a forest district of 3 acres, and is 

 situated east of the cemetery on Wenham Street. The timber and 

 brush here are the same as in the other locality, and the egg clusters 

 of the gypsy moth were also first discovered here during the winter 

 of 1909-10. Unfortunately, several clusters were killed with creosote 

 before my first visit. The clusters still present were estimated by Mr. 

 Souther and myself at about 600. On account of the young age of the 

 colony and the considerable size of the clusters probably no disease 

 had appeared among the caterpillars of the preceding year. 



The remaining part of the wilt material was planted among the cater- 

 pillars of this locality on the same day and in the same manner as in 

 the first colony. Here, also, most of the caterpillars at this time had 

 just undergone the third molt. 



The estimate of the fresh clusters, which was made by the local super- 

 intendent and myself Oct. 7, 1910, was about 400, from which the first 

 5 found were used for microscopical examinations. The result is as 

 follows : 



Cluster 1. 



Unfertilized eggs, . . . - \ 



Eggs with dead embryos, . 12 / = 4.11 per cent, or about 4 per cent. 

 Eggs apparently alive, . . 280 =95.89 per cent., or about 96 per cent. 



Total, . . . .292 eggs. 



