BULLETIN" 1371, U. S. DEPARTMENT OF AGRICULTURE 
plant. Willcocks 6 on the other hand reports only 12 per cent of the 
total eggs deposited on the bolls in Egypt, stating, however, that these 
data are based on too few records. No doubt the percentage of eggs 
deposited on different parts of the plant depends to a great extent on 
the state of growth of the plant and the ratio of bolls to foliage. 
In the summer of 1921 observations were made on plants growing 
in the field to determine the number of larvae reaching the bolls 
from eggs deposited on parts of the plant other than the bolls. These 
tests were begun August 20. Three sets of plants, two plants per 
set, were selected, and all bolls then on the plants were removed. 
Thus the bolls as well as the larvae considered in the experiment were 
produced after the experiment began. After a sufficient number of 
bolls were set, no more were allowed to form. Every two days all 
eggs were removed from the bolls on one plant in each set. The 
other plant served as a check. On September 14 all the bolls were 
removed from the plants and examined for larvae and exit holes. 
The results of this test are given in Table 1. 
Table 1. — Infestation of green bolls from which all pink bollworm eggs had been 
removed and of bolls on check plants 
Plant No. 
■ Number 
of bolls 
Number 
of eggs 
removed 
Total 
number 
of larvae 
and exit 
holes 
Number of larvae 
and exit holes 
per boll — 
Test ! Check 
plants ; plants 
Percent- 
age dif- 
ference 
1 ' 
19 1,326- 
15 
104 
84 
111 
151" 
51 
116 
5.47 
2.3 
2 
5.60 
3 .... 
18 
18 
11 
12 
722 

741 

6.17 
26.5 
4 
8.39 
5. 
4.64 
52.0 
6 
9.67 
Average per boll... 
158.1 
5. 54 7. 80 
28.9 
1 Bolls on check plants not included. 
The most striking points about these results are the great number 
of eggs removed per boll and the comparatively little reduction (28.9 
per cent) in infestation brought about thereby. The proportion of 
eggs deposited in other places than on the bolls is likely to have been 
higher in the case of these plants than is normal, because of the limit- 
ing of the number of bolls that grew on them. Considering, however. 
Loftin's 7 figures (51.7 per cent), first referred to, it would appear 
that even with only an equal chance for the larvae hatching from 
eggs on the bolls to enter the bolls, the infestation should be reduced 
by at least 50 per cent by the removal of all eggs from the bolls. 
From these observations it must be assumed either that the 
position of the egg on the plant has little to do with the ability of 
the young larva finally to enter the bolls, or that in this particular 
experiment, with such a number of eggs present, many of them were 
so near the bolls that the young larvae hatching from them were in 
almost as favorable a position as those hatching from eggs on the 
«F. C. Willcocks. The insect and related pests of Egypt. Volume I. The insect and related pests 
injurious to the cotton plant. Part I. The pink bollworm. 335 pp., illus. Cairo. 1916. (Sultanic 
Agr. Soc.) 
* U. C Loftin. K. B. McKinney, and W. K. Hanson. Op. cit. 
