46 



Cluster 5. 



Unfertilized eggs, ^ - \ ^ Qr about Q5 



Eggs with dead embryos, . 4 J 



Eggs apparently alive, . . 58 =93.55 per cent., or about 93.5 per cent. 



Total, .... 62 eggs. 

 The average of these 5 clusters gives the following result : 



Dead eggs, .... 9 = 7.63 per cent., or about 7.5 per cent. 

 Eggs apparently alive, . . 109 =92.37 per cent., or about 92.5 per cent. 



Total, . . . .118 eggs. 



Since a normal cluster contains on the average 433 eggs with appar- 

 ently living embryos, and this place, in which Flacherie had operated, 

 contained only 109 eggs with apparently living embryos on the average 

 per cluster, about 4 clusters were necessary to equal the size of a 

 normal one. The number of fresh clusters, which were estimated to 

 be about 250, thus must be reduced to about 65. The number of ap- 

 parently living eggs of this locality therefore was decreased, after the 

 wilt had worked, to about 15 per cent. 



For the second experiment a small isolated group of oaks, about 

 eighty years of age, was selected. This place is situated near the 

 railroad station, Beverly Farms, between the railroad track and the 

 ocean. The caterpillars of the gypsy moth have always appeared here 

 only in small numbers, and there were hardly more than one dozen 

 clusters in the spring of 1910, according to our estimate. It must 

 be mentioned, especially, that this locality is always exposed to very 

 strong winds. 



Flacherie, artificially developed by the assistant of the division agent, 

 was planted among the caterpillars at this place on June 25, 1910, in 

 the same manner as in the first locality. Considering the heavy breeze 

 the material was placed in a wooden box, which was then fastened 

 between limbs; thus the wind was not able to carry off the whole 

 material. Most of the caterpillars of this place were about ready 

 at this time to undergo the third molt. 



On Sept. 13, 1910, this locality was visited again. The wilt had 

 done very considerable damage to the caterpillars. Although the place 

 was carefully searched with Mr. Holmes's assistance, we could find but 

 2 fresh clusters. One of these is especially remarkable, as it lacks com- 

 pletely the protecting covering. The microscopic examination of both 

 clusters gave the following results: 



