80 DECIDUOUS FRUIT INSECTS AND INSECTICIDES 
THE FIRST GENERATION. 
FIRST-BROOD EGGS. 
Incubation period.—In the preceding pages the time and extent of 
egg deposition have been considered as habits of the moths. In view 
of the abundance of eggs laid on the apples in the cages, it was not pos- 
sible to count the eggs and determine the incubation period for individ- 
ual eggs. But, as shown in Table XII, records were taken at the time 
of hatching of the first and the last eggs of each group of apples con- 
taining eggs of a given age, which merely shows in a general way the 
extent of the variability during the incubation. 
TaBLe XII.—First-brood eggs. Incubation period of eggs laid in rearing cages. 
ie a 
Date of— | Date of— 
No. Days of No. g Days of 
of obser- incuba- || of obser- incuba- 
vation. | Deposi- | Hatch- tion. vation. | Deposi- | Hatch- tion. 
tion. ing. tion. ing. 
eee ee June 23 | June 29 JG) (2 asa July 3] July 12 9 
DE desea Ue June 24 |...do..... O20 Se eee July 45 |\S=dorsees 8 
5 ee June 25| July 1 Gullgzle ees Jilly On| =eaGOree ns 7 
Me acts Gdoszea- July 2 7 | 22 mer Oy aane July 13 8 
5a eae June. 26) adoneres (ie || 8 eae ee ed Dilly w60| = sdoeere- 7 
(Re are dors === July 3 (Ele Bae July 8] July 14 6 
Mcicewise June 27 | July 4 Tb eee ee ee Olena July 15 7 
Sie O02 24, dUliy | 5 Sil e2O eee eae Jitliv; Osea adoree4 6 
Oe een June 28 | July 6 Sal aire Bee Jialiyeel0))|Ps. doses. 5 
il) esac June 29 | July 7 Sri p28 here e. -do....] July 16 6 
LE eee 22d0}e-- | Jubyae Ss Dill29" aoe s ee Aieihye at oles sc 5 
12 ees Gloy Sem cihoihia 2) LOW SO Leese Choy SSM bl hye alyy 6 
Witenes June 30} July 8 8) | eileen as July 12} July 18 6 
I icra July 1) Jul 9 SB Allinoee eee Ove s =| vote 09) 7 
l5esecee Oss. July 10 Onl G33 ences July 13 | July 21 8 
1G. eS a0 Osn.<e July 11 LO} |nS4o ee es July, W4 |. .<do-: == 7 
1 eee Iulyee 2; a. 2d0cr-<< OF doe Severe ae Jd052 == July 22 8 
Ie sees ACU) Sac July 12 LON || paGseeeae July, 15; |<. sdo-2-. = 7 
: | 
The difference of one to two days in the time of hatching indicates 
an existing difference in the embryological development originating 
previous to the time of oviposition. Similar observations were made 
in 1909 by the writer with eggs of the grape root-worm which had all 
been laid by a single female at the same time. On hatching, these 
egos showed a variation of 2 days in the time of incubation. Table 
XII, representing a summary of observations of the previous table, 
shows an average of 7.33 days for the entire egg period, with a maxi- 
mum of 10 days and a minimum of 5 days. 
TaBLE XIII.—IJncubation period of first-brood eggs. Summary of Table X IT. 
Days of 
Observations. incuba- 
tion 
A VOTE EOE acme ee Heres 
Mascimulmntes sacepeeee ser 10 
Minimum: 352252 s0ke eens 5 
