BULLETIN 438, U. S. DEPARTMENT OF AGRICULTURE. 
TaBLe VII.—Larval life history of the pear leaf-worm at Wenatchee, Wash., 1915. 
3d molt. 
Cocoon. 
Date of— 
No. ora 
atch- 
ing ist molt. | 2d molt. 
te Asn 1G acAsprEe 2a eam ae as 
2| Apr. 18) Apr. 25| May 2 
Bit eeea Loar gens ley ieKo KO dee sel AN Oy ean Ao) 
Ac A pre L9n ss 2doms 24|Aipr. 28 
5 be does) Ajprs,26)|\7Apr 130 
6/22 .doz = ado 425 Maya) i) 
Gee doe BGO EEE Et donee 
Sie tdoz =.00- ...| May '/4 | 
9 |-.-do- BOO me events ded 
10 |..-do- SCO S Ss UL Sae8 ae 
I SAC Ae Seno ORs dalaReateee S| 
12) eApre 21) 2 dors ss) Mavs 2 
13) dO see ee GOs asia s| 
14 |..-do-~ =- G0: 
LSE aos Apr. 27 | May 5 
AGUIPEACOUEN Sale COs a bs he toe 
17} Apr. 22 | Apr. 28 | May 5 | 
US Hb ZsQou 23) |e Oe Haale ee OKOA Bee 
A Dh ERGO Ras Ones eee dore ae 
20 eed Osa alee OO a! ec aes Le 
21 Ge doee ee Aue 129 
22 ee Oz ete Oe 
23) (Ed Ose AeA ESTO 
24 | Apr. 24 | Apr. 29 | 
Zod ate. O/-ta, ties SC Ole 
7A yal es Soest mE ly Se ee a Apr. 29 | 
Pet fcrcecseteeaees Parl | bie Seana eae May 8 
PASE IG Melee sae Sie Spares May 9 
ZO ee cee Soa ee aceelle Cowes 
GOMER See. elms Leak A May 15 
Bi TF Seese ees See ae eel ene doses 
BO) ety ran | persian SU AR Ee domeae 
ia a ee ete aha Tee Ae May 17 
SAE sek nl Sl ey rere aah ae ea A 
Sa ee ea al Hx sea | ae 
AOI oy ho sien aeatitas | ae vidal NK ah ere 
Oba ea Sats cheese ges aera Se ak 
Length in days. 
1 
iales 
Ag 8 
Saleh as 
4 
5 
8 
Soha GN 
6) ae 
7 tao 
Vaiss aan Ale 
Pr teine 
CaN Na 
Ti\e dees 
At 
Bes 9 
Pe 6 
nas 6 
Prt 8 
a 8 
lu aie 8 
TaBLe VIII.—Summary of Table VII. 
Instar. Maximum. Minin Average. 
Days. Days. Days. 
pS NR 7 5 6.1 
2s SRE eh ey Su 8 3 6.0 
Brena tee wee cee 9 6 7.6 
CPP HOR AGA RES arEAG 10 6 8.4 
Woy ea a et a A | 28.1 
In ascertaining the larval life history at Wenatchee, it was neces- 
sary, owing to the distance of the mfested orchard, to rear the larve 
on leaves kept in water in the outdoor rearing shelter. These had 
to be renewed every 4 or 5 days, and the larve transferred to the 
fresh leaves. It will be noted that there was a high mortality among 
the larvee, and this may be attributed to the fact that the larve had 
to be handled more or less, and that they did not always have per- 
fectly fresh food upon which to feed. It is probable, also, that the 
periods between molts were lengthened by this abnormal method of 
rearing, although observations in the field indicate that the figures 
for the total larval life are approximately correct. In 1915 most of 
