162 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
All larvae upon which records of the overwintering brood were based 
were collected in the fall. The number of individuals used to deter¬ 
mine the duration or time of occurrence of any stage was made to cor¬ 
respond, as far as possible, with the degree of variation to be expected 
and the economic importance of the phenomena in question. As for 
instance the period of spring emergence of moths is of first importance 
and is exceedingly variable, and for this it was aimed to procure over 
3,000 overwintering larvae. On the other hand the duration of the 
incubation period in midsummer is relatively constant and of little 
economic importance and records of 20 to 30 eggs per day were all 
that were attempted. To check up insectary records larvae were col¬ 
lected under bands at intervals of three days in two orchards in 1918 
and in three orchards in 1919. 
During the first season of the writers’ residence in this region, that of 
1918, there were three full broods and a partial fourth brood of codling 
moth larvae. Previous records have shown three broods for this 
region. As far as the writers are aware four broods are recorded from 
only one other state, New Mexico. The season of 1918 was very 
favorable to codling moth development, the summer as a whole and 
month of August in particular being remarkable for high temperatures. 
During the heat of summer all stages were passed rapidly. 
The record of emergence, for this season, of the overwintering brood 
of codling moth extended from April 29 to June 3, and records of hatch¬ 
ing of first brood larvae from May 17 to June 13. The earliest first 
brood moths were secured June 15 and the first second brood larva, 
June 25. From this date until the early part of October the second 
and following broods continued hatching daily. Moths of the second 
and third broods began emerging July 27 and September 12 respec¬ 
tively, and their offspring, the larvae of the third and fourth broods, 
began hatching August 4 and September 23 respectively. The sec¬ 
ond and third, and third and fourth broods overlapped to such an 
extent that it was impossible to separate them even in a general way 
either by field observations or band records. Most larvae spinning 
cocoons after September 1 entered hibernation. Harvest of Jonathan 
apples was nearly over at this time and harvest of Ben Davis started 
by September 15. As a result many undeveloped larvae of the third 
and nearly all of the fourth brood were carried out of the orchard with 
the fruit. 
The feature of the seasonal history of the codling moth in 1919 was 
the length of the period between the beginning of emergence of over¬ 
wintering moths and the beginning of hatching of larvae in economic 
numbers. The earliest record of moth emergence was April 20 and 
by the middle of May nearly half of the brood had emerged. The first 
