THE CODLING MOTH ON PEARS IN CALIFORNIA. 19 
Walnut Creek, three eggs were found on foliage in the field, and on 
May 2 eggs were numerous throughout the valley. At Suisun, Cal., 
larvee were hatching April 29, and on May 3 young larve were quite 
numerous in some of the warmer sections of Suisun Valley, indicating 
that eggs were deposited in numbers some two to three weeks before, 
that is, from the 12th to the 20th of April. 
Incubation period.—One noticeable difference between the life his- 
tory of the codling moth in California and in the country east of the 
Rocky Mountainsis the increased length of time required for incubation 
of the first-brood eggs. As a rule there is considerable cool weather, 
especially at night, during the months of April and May. This was 
especially noticeable in the vicinity of Walnut Creek in 1909. The 
time required for incubation varied from 17 to 22 days, averaging 
20.05 days for the individuals under observation. The individual 
record for 56 eggs, deposited from May 8 to 11, are given in Table VI. 
In the spring of 1910 the period of incubation was not observed 
individually for many eggs, but all indications were that the incuba- 
tion period varied from a minimum of 15 days to a maximum of over 
30 days, with the majority requiring about 25 days. 
TaBLE Vi.—Life cycle of the first generation, Walnut Creek, Cal., 1909. 
Date of— Days for— 
Individ- 
ual No. | Egg dep- Pies || oben! Me Emer- Feed- |Making : Total 
osition Hatch leaving ee gence of segs ing of | of co- Fupal life 
(night). 8. fruit. , moths. ‘| larva. | coon. | } “| eycle 
| 
Ue Suge gas WENA tei |My eo deo Sallnees seco) bos semeeee A Re eared sean aan beaepraal yee acces 
De eee 8 | ZOU ees 2 See Sse ca sem Sik ate oe PA eee ste Sal Sell cats oe SA eee 
estate es 8 AS eee eS Ol aR ane Meme eens 2 (in| roars c dl etertes slice semen | soe amend 
Bee Osekic 8 | DS yemcvee es oe te ciasia sees cmrenrle cians 20 Nias tina | Soeseec eens ce oelee eens 
eee ee 8 | Sal heeaee eerie smeared eel set acme DONS Seed | eee ee eel ee ee 
Gia 8 | 28 | June 24) July 1] July 24 20 27 7 23 77 
f(s eee 8 28 | 7 eee See E eee 20 | 0} hascee 8 Beate see ae 
Peers Qabioers 8 28 | 29 4 25 20 | 32 5 21 78 
ee ene 8 29 29 5 23 21 31 6 18 76 
LOB esses 8 Dh Pett se eyes <font eer 710 eee cere eR eSeae a seas eee 
Mie stecac- 8 29 24 2 18 24 26 8 16 71 
ime Leh 8 29 BONS peepee 05 lle cps cick 21 Bil irae ein tl eerste oe esate eee 
1S Ee eect 8|% 29 DOIN ae eS Le RNa? Bike he 21 OL eee | cee er | eek > Sete 
eee Ses a5 8 Oil eas ene ta Sete teens eter teeters 71 NORE Pct one Cae ee eee mnea 
Gas ae 8 28 CEN Oe RA Se eT See 20 Dip Noche ise ars| hes coat ere eio ee 
Na) Nees Sea 8 30 | 2A PUNE) SOc eeasees 22 25 Gall :S 354222 | see oe 
1 (PS OETA § 30 23 30) eee eases 22 24 Wal Peee roe aaeS ze see 
ISS See ae 8 | Z 
it oan a eee 8 
20 ot 2 bc 8 
rl CA 8 
vA eee 9 
pe ee eee 9 
DE cla oe 9 
hae he 9 
7 eS Re 9 
7a oie eee 9 
7. ee Ie 9 
Oe es. Be hae 9 
BU Aveo sae 9 
sy A Sees § 9 
CP ee eer 9 
BO oe ais aie 9 
Cr Beas 9 
Bob Sah ee 9 
6h See 9 
