28 
Table I. — Duration of egg stage of codling moth — Continued. 
Date laid. 
Number 
Date 
Number 
laid. 
hatched. 
hatched. 
1902. 
27 
Sept. 5 
8 
Sept. 6 
14 
Sept. 8 
2 
61 
Sept. 8 
3 
Sept. 9 
4 
Sept. 12 
32 
Sept. 15 
2 
14 
Sept. 9 
1 
Sept. 6 
11 
Sept. 15 
1 
40 
Sept. 8 
3 
Sept. 9 : 5 
Sept. 12 
3 
Period of 
incuba- 
tion. 
Total ef- 
fective 
tempera- 
ture. 
Average 
effective 
tempera- 
ture. 
1902. 
Aug. 27 
Aug. 28 
Do 
Aug. 29 
CORDI.EY 
Mav7 
"Do 
June 1 
Mav 12 
Days. 
243 
o p 
278 
307 
360 
269 
295 
364 
428 
216 
269 
428 
254 
286 
349 
298 
285 
o jp 
The results under normal orchard temperature give the length of 
the stage from 9 to 18 days, with a weighted average of 11 da3^s. This 
average is longer than has been given by other authors, which may 
be accounted for b}^ the fact that it is the usual custom to keep the 
eggs in laboratories rather than under normal orchard conditions, and 
that the times of the laying of the eggs were estimated. 
HATCHING or THE EGG. 
Recent authors are quite well agreed as to how the larva breaks or 
eats its wa}^ out of the shell. Professor Slingerland was most proba- 
bly the first to observe this operation. He states that the larva came 
out of the egg near the edge at one end through an irregular crack in 
the shell. (PI. Ill, es.) The writer has never observed this emer- 
gence, but upon examining many egg shells an irregular crack was 
always found which was almost always at one end of the shell. 
CHANGES DURING INCUBATION. 
When laid the egg is of a translucent pearh^ color, often with a 
j^ellowish tinge. Observations upon 88 eggs show that from 2 to 6 
da3^s with a weighted average of 3 da3\s after being laid a red ring 
makes its appearance. This ring appears graduall}^ at first whitish, 
then yellowish, and later quite a brilliant red. B}' observations upon 
56 eggs it was found that in from 7 to 10 days, with a weighted aver- 
age of 8.1: da3^s after being laid, the egg loses the ring and in its place 
the larva can be seen, the " black spot," which consists of the head 
and cervical shield, l^eing the most conspicuous pai't. 
Professor Gillette states that his assistant, Mr. E. P. Ta\dor, found 
the red ring to appear in from 2 to 3 diiy>^ after laying and the black 
