32 



The average of these clusters gives the following result: — 



Dead eggs, .... 8 = 7.34 per cent., or about 7 per cent. 

 Eggs apparently alive, . . 101 =92.66 per cent., or about 93 per cent. 



Total 109 eggs. 



Since this locality, which had been infected with the wilt, showed 

 only 101 eggs with apparently living embryos on the average per 

 cluster, about 4 clusters would be equal to a normal one. The fresh 

 egg clusters, which were estimated at about 80, thus have to be re- 

 duced to about 20. The number of apparently living eggs in this 

 infested locality has thus decreased to about 4 per cent. 



A third locality in which the wilt appeared naturally was somewhat 

 closely inspected. A small isolated wood of about 3,000 square feet 

 is situated on Main Street, about 500 yards south of Wood's Corner. 

 Tie trees consist of oaks a hundred years or more of age, and the 

 place is free from underbrush. The gypsy moth caterpillars were very 

 numerous here in the summer of 1909, but no definite statement can 

 be made as to whether or not there. was disease among them. If the 

 disease was present, it was doing little harm, as otherwise dead eater- 

 pillars in large numbers would have been noticed, without doubt, by 

 the division agent or the local superintendent. Mr. Worthen estimated 

 the number of clusters present in the spring of 1910 at about 400. No 

 artificial means for destroying the gypsy moth were undertaken. Meas- 

 ured in a straight line this place is at least 1 mile from the nearest 

 of the two localities previously mentioned. Flacherie was noticed here 

 at a time when most caterpillars were in the fourth molt. Here, too, 

 the disease- worked considerably among the caterpillars. It was hard 

 to find even 50 clusters when Mr. Worthen and I estimated the freshly 

 laid ones, on Aug. 26, 1910. For comparison the first 5 clusters found 

 were collected and examined. They gave the following results : — 



Cluster 1. 

 Unfertilized eggs, . . . - \ 

 Eggs with dead embryos, . g j" = 1 1-27 per cent., or about 11 per cent. 



Eggs apparently alive, . . 63 =88.73 per cent., or about 89 per cent. 

 Total, .... 71 eggs. 



Cluster IS. 

 Unfertilized eggs, . . 1 \ 



Eggs with dead embryos, . 10 J " ^"'^^ P®'" "^^^'^ °^ ^^°"* 1° P^"^ <=^"*- 

 Eggs apparently alive, . 96 =89.72 per cent., or about 90 per cent. 



Total, . . .107 eggs. 



