CODLING MOTH IN NORTHWESTERN PENNSYLVANIA. 91 
Taste XXVI.—Longevity of male and female moths of the first brood. Summary of 
records of 149 individual moths. 
Male. Female. Male. Female. 
Length | Number} Length | Number || Leagth | Number Length | Number 
oflife. |ofmoths.| oflife. |ofmoths.|| oflife. |ofmoths.| oflife. |ofmoths. 
Days. Days. Days. Days. 
2 3 2 1 14 2 14 7 
3 1 3 4 15 3 15 3 
4 3 4 2 16 3 16 6 
5 1 5 2 17 2 17 7 
6 1 6 4 18 1 18 2 
7 5 7 CF eacce SoS come c eee 19 1 
8 6 8 by ae cor em llsoc conan 20 1 
9 9 9 CB Es RT |e 21 1 
10 4 10 Ui MNBeoasosseellesacooates 22 2 
11 3 11 8 — SSeS 
12 5 12 7 57 92 
13 5 13 10 
Taste XXVII.—Longevity of male and female moths of the first brood. Summary of 
Table XX VI. 
Life of Life of 
Observations. male female 
moths. | moths. 
Days. Days. 
AVOTA RO nc tren ceceeceeeee = 9.79 11.47 
Maxim: ace ieee ec 18 22 
Mimi eee ye 2 2 
On further testing the rearing results by taking the dates of the 
maximum emergence of the spring brood of moths (June 24) and the 
emergence of moths of the first brood (August 26) it will be found 
that 63 days elapsed. But since the emergence of moths of the first 
brood was very gradual, reaching its maximum first at the close of 
the season (fig. 22), it becomes evident that the average of 58.5 days 
is fairly accurate. 
THE SECOND GENERATION. 
SECOND-BROOD EGGS. 
Incubation period.—From two to three days after egg deposition, 
a semicircular red ring appears within the egg, which later disappears 
as the embryo attains further growth. Commonly this condition of 
the egg is referred to as the ‘“‘red-ring” stage. A black spot ap- 
pears in the egg from two to three days previous to hatching, and is 
caused by the dark-colored portions of the head and prothorax of 
the future larva which are partly visible through the eggshell. In 
taking observations on these features of incubation no fixed time can 
be given, as these changes set in and disappear gradually with the 
growth of the embryo or young larva. It is of value to know the 
significance of the ‘red ring’”’ and the “black spot,” as the age of 
the eggs can thus be approximately determined in the field. 
In the cages eggs were laid daily during the entire egg-deposition 
period, which extended from August 6 to September 22, and a full 
record of the incubation period was kept during this time (Table 
XXVIII). 
