672 
Journal of Agricultural Research 
Vol. XXX, No. 7 
No more Anastatus were liberated 
in this area until the spring of 1915, 
when the outside area of Peabody and 
the surrounding towns were solidly 
colonized with Anastatus. The effect 
of this later colonization is shown in 
the evenness of parasitism manifested 
in the collections made 2 and 3 miles 
from the center of the original Peabody 
colony. 
After 1921 the gipsy-moth infesta¬ 
tion in this area was too light for 
general collection of eggs to obtain 
Anastatus for colonization. In each 
of the following years sample collec¬ 
tions of gipsy-moth eggs when possible 
of 10 egg clusters each, have been 
made to determine the percentage of 
parasitism in this area. About 40 col¬ 
lections were made at points scattered 
over the area where general collecting 
was previously done. The average 
percentage of parasitism of these eggs 
by Anastatus has been, for 1921-22, 33; 
for 1922-23, 23; and for 1923-24, 18. 
In order to determine the average 
percentage of parasitism by Anastatus 
of the gipsy-moth eggs in a town which 
should be representative several years 
after colonization, 10 egg masses were 
collected from about 50 points in the 
town of Weston, Mass. The egg col¬ 
lections were made in the woodland 
near the roadside or from roadside 
trees. Each road in the town was 
included in the survey.' The average 
percentage of parasitism of the gipsy- 
moth eggs for each year during the 
time covered by the survey was, for 
1917-18, 21; for 1918-19, 19; for 1919- 
20, 13; for 1920-21, 33; for 1921-22, 
34, and for 1922-23, 21. 
During the last five years repre¬ 
sentative collections of gipsy-moth 
eggs have been made from the fol¬ 
lowing five towns in Massachusetts: 
Burlington, Dover, Lynnfield, North 
Reading, and Wilmington. About 17 
points were chosen in each town and 
collections of 10 egg clusters when 
possible were made at each location. 
The average percentages of parasitism 
of the gipsy-moth eggs by Anastatus 
for the five years in each town are 
shown in Table IV. 
The figures for the year 1921-22 
show the maximum percentage of para¬ 
sitism of gipsy-moth eggs by Anastatus 
which has been obtained over a large 
area in Massachusetts since the estab¬ 
lishment of this parasite in New Eng¬ 
land. 
Table IV.— Average percentage of par¬ 
asitism of gipsy-moth eggs by Anastatus 
bifaciatus as indicated by representative 
collections made in five towns in Mas¬ 
sachusetts 
Year 
Burlington 
Dover 
Lynnfield 
i 
North Reading 
Wilmington 
P. ct. 
P. ct. 
P. ct. 
P. ct. 
P. ct. 
1919-20. 
14 
14 
11 
16 
16 
1920-21. 
24 
34 
19 
23 
26 
1921-22. 
35 
37 
31 
35 
34 
1922-23.. 
32 
31 
28 
25 
30 
1923-24 “. 
28 
24 
14 
11 
18 
a The collections of 1923-24 were made somewhat 
earlier than usual, possibly before some of the Ana¬ 
status were through ovipositing; the percentage of 
parasitism is therefore thought to be rather low. 
PERCENTAGE OF PARASITISM BY 
ANASTATUS AND SCHEDIUS OF 
GIPSY-MOTH EGG CLUSTERS AT 
VARIOUS HEIGHTS IN THE TREES 
Collections of gipsy-moth eggs to 
determine the percentage of parasitism 
by Anastatus and Schedius of the eggs 
at different heights in the trees have 
shown that the parasitism is approxi¬ 
mately the same over the entire tree. 
The collections of eggs for data on 
Anastatus were made in four separate 
locations. The egg clusters collected 
from the trees at distances of from 1 
foot to 6 feet from the ground were 
termed ‘Tow-point” collections; those 
collected at heights of from 20 to 55 
feet were termed “high-point” col¬ 
lections. Five egg clusters were col¬ 
lected at the low and five at the high 
points from each of the trees selected 
in the four locations. Table V contains 
a summary of the examinations of the 
eggs. 
The average percentage of parasitism 
of the eggs collected from the low points 
was 37.0, and for those from the high 
points 35.8. The difference between 
the average size of the lower egg clus¬ 
ters and that of the higher could ac¬ 
count for this difference, the higher 
being slightly the larger. Studies of 
the percentage of parasitism of egg 
clusters of different sizes have shown 
that the percentage of parasitism in¬ 
creases as the size of the cluster de¬ 
creases. 
