PROGRESS REPORT ON THE EUROPEAN CORN BORER 
109 
eggs per cluster is subject to considerable variation. From 1 to 162 
eggs have been found in individual clusters. Jablonowski 10 , quoting 
from observations made by his assistant, Gabriel Bako, states that in 
Hungary " each cluster contained a minimum of from 22 to 35 eggs." 
Table 37 gives data relative to the average number of eggs per 
cluster deposited by females in confinement at Arlington, Mass. 
Table 37. — Average number of eggs of Pyrausta nubilalis per cluster, New 
England, 1918 to 1921 
Generation 
Number 
of clusters 
counted 
172 
431 
1,666 
2, 884 
3,539 
3,255 
260 
1,127 
Average 
number 
of eggs 
per clus- 
ter 
Average 
maxi- 
mum 
number of 
eggs per 
cluster 
perfemale 
Second generation, 1917-18 . ... _ _ _ 
20.0 
17.3 
13.9 
14.0 
12.2 
13. 9 
19.2 
23.4 
34.0 
First generation, 1918. . _ .... _________ 
34.6 
Second generation, 1918-19 _ ______ . ___ 
31.2 
First generation, 1919 _____ 
33.0 
Second generation, 1919-20 _ ____ _ ______ 
40.0 
First generation, 1920. 
30.8 
Second generation, 1920-21 ... . _______ _ _ __ 
38.7 
35.2 
Total 
13, 334 
Average .___ _ __ _____ 
14.6 
Table 37 shows that the average number of eggs per cluster 
varied from 12.2 to 23.4 in the different generations of females 
under observation, with an average of 14.6 eggs per cluster for 
the entire series. The last column in this table pertains to the 
average maximum number of eggs per cluster deposited by any one 
female in the generation. 
At Silver Creek, N. Y., there were an average of 14.5 eggs per 
cluster in 747 egg clusters deposited in confinement during 1923, 
and an average of 16.7 eggs per cluster in 1,060 egg clusters de- 
posited under the same conditions in 1924. Comparative figures 
for Sandusky, Ohio, observations show an average of 14 eggs per 
cluster in 575 egg clusters during 1923, and an average of 16.8 eggs 
per cluster in the 1,746 egg clusters upon which observations were 
made in 1924. A total of 731 egg clusters collected in the field in 
Ohio during 1924 contained 15.5 eggs per cluster on an average. 
The average number of eggs per cluster in the one-generation areas 
of New York and Ohio compares very closely with the average 
for the two-generation area of New England. 
DAILY RATE OF OVIPOSITION 
In confinement the daily rate of oviposition varied with different 
females and according to the temperature conditions. In some in- 
stances a single female deposited several egg clusters within a 
24-hour period, whereas in other instances a period of several days 
elapsed between the deposition of successive egg clusters. Table 
38 gives data relative to the daily rate of oviposition of females 
confined in individual lantern-globe cages at Arlington, Mass. 
10 See footnote 1. 
