WALNUT APHIDES IN CALIFORNIA. 
29 
Table IX,— Life-cycle record of the progeny of four viviparous females of Monellia 
caryella, Walnut Creek, Cal., 1912 — Continued. 
FEMALE NO. 3; DEPOSITED 16 YOUNG. 
Date of— 
Form of individual. 
No. of larva. 
Hatch- 
ing. 
Molt 1. 
Molt 2. 
Molt 3. 
Molt 4 
(becom- 
ing 
aclult). 
Life 
cycle. 
1 
Oct. 16 
16 
16 
17 
17 
17 
17 
18 
18 
Oct. 21 
21 
21 
(?) 
(?) 
(?) 
(?) 
(?) 
(?) 
Oct. 27 
27 
27 
(?) 
(?) 
(?) 
(?) 
(?) 
(?) 
Nov. 3 
3 
3 
(?) 
(?) 
(?) 
(?) 
(?) 
(?) 
Nov. 7 
7 
7 
8 
8 
8 
8 
8 
9 
Oviparous female 
do 
Days. 
22 
2 
22 
3 
do 
22 
4 
do 
22 
5 
.*.... do. . 
22 
6. . 
...do 
22 
7 
do... 
22 
8 
do 
21 
9. .. 
....do. 
22 
10i 
do... 
Hi 
do 
121 
do 
13i 
...do... 
141 
.....do 
15i 
do 
16i 
do 
FEMALE NO. 4; DEPOSITED 8 YOUNG. 
1 
Oct. IS 
18 
18 
18 
Oct. 22 
22 
22 
22 
Oct. 27 
27 
27 
27 
Nov. 2 
3 
4 
4 
Nov. 
9 
9 
Oviparous female 
do 
20 
2 
22 
3.... 
do 
22 
4 
do 
22 
do 
6' 
do 
71 
do 
8i 
do 
Died prematurely. 
SUMMARY. 
Life cycle (20 oviparous females). 
Days. 
22 
14 
18.92 
3.7 
4.5 
5.7 
5.6 
First instar (13 individuals), average. . . 
Second instar (13 individuals), average.. 
Third instar (11 individuals), average... 
Fourth instar (11 individuals), average . 
The viviparous forms, so far as the author has observed, all 
develop wings. 
The eggs of this aphis are larger than those of the American walnut 
aphis and measure on the average 0.536 mm. in length and 0.222 mm. 
in maximum width. They are elongate-oval in shape, rather feebly 
shining, and have a softer shell than is found in the eggs of the 
majority of plant-lice, but one not so soft as is that of CJiromapliis 
juglandicola. They are placed either singly or in groups of two or 
three around the axils of the buds or in crevices in the bark and in 
scars caused by fallen leaves on the smaller limbs and twigs. Ovipo- 
sition is in. progress during the months of October and November, each 
oviparous female laying on the average about 12 eggs. Owing to the 
