28 
BULLETIX 100, U. S. DEPARTMENT OF AGRICULTUEE. 
Table VIII. — Divergences of structure between Monellia caryx Monell and M. caryella 
Fitch. 
Form. 
Monellia caryx Monell. 
Monellia caryella Fitch. 
Winged viviparous female. 
Pupa of viviparous female . 
Oviparous female 
Antennal joint III very slightly 
thickened basally. 
Sensoria on antennal joint III 
occupying basal half or two- 
thirds. 
Antennal joint VI and its spur or 
filament subequal, or VI less 
than spur. 
Dusky knee spots often present. 
Four longitudinal rows of capitate 
spines. 
Smaller than the viviparous fe- 
male. 
Four longitudinal rows of capitate 
spines. 
Antennal joint III quite notice- 
ably thickened for its basal half. 
Sensoria on antennal joint III oc- 
cupying basal third. 
Antennal joint VI one-third as 
long a sain as its spur or filament. 
Dusky knee spots absent. 
Six longitudinal rows of capitate 
spines. 
Larger than the viviparous fe- 
male. 
Six longitudinal rows of capitate 
spines. 
LIFE HISTORY AND TECHNICAL DESCRIPTIONS. 
Life-history studies on this plant-louse began in August, 1912, at 
San Jose, Cal., but no rearing work was done until the appearance 
of the sexed forms in September. Observations taken in August 
and September indicated a development of the summer generations 
similar to that found in Monellia caryse. This was further confirmed 
by studies during 1913. The sexed forms were studied at Walnut 
Creek and San Jose, Cal. In both localities these did not appear until 
late in September, even on trees heavily infested. The aphides re- 
mained on the trees as long as there were leaves on which they could 
subsist and were to be found until mid-November. After September 
the great majority of aphides deposited were oviparous, and of these 
the males were extraordinarily scarce, the writer observing only one 
individual of this sex among hundreds of oviparous females. Table 
IX indicates the life cycle of plant-lice deposited by four viviparous 
females and shows the preponderance of the sexed form over the 
asexual in the late fall. 
Table IX. — Life-cycle record of the progeny of four viviparous females of Monellia 
caryella. Walnut Creek, Cal., 1912. 
FEMALE NO. 1; DEPOSITED 3 YOUNG. 
Date of— 
1 
No. of larva. 
Hatch- 
ing. 
Molt 1. 
Molt 2. Molt 3. 
Molt 4 
(becom- 
ing 
adult). 
Form of individual. ^{j 
1 
Oct. 4 
4 
Oct. 7 
Oct. 10 
11 
(?) 
(?) 
Oct. 16 
IS 
1 Days. 
Winged viviparous fe- 12 
male. 
Oviparous female 14 
do 
2 
31 
FEMALE NO. 2; DEPOSITED 6 YOUNG. 
1 
Oct. 12 
12 
12 
12 
12 
12 
Oct. 15 
15 
15 
1.5 
(?) 
to 
Oct. 18 
18 
19 
19 
(?) 
(?) 
Oct. 21 
21 
22 
23 
(?) 
(?) 
Oct. 2S 
28 
29 
30 
29 
30 
Oviparous female 
do 
16 
2. .. 
16 
3 
do 
17 
4 
do 
18 
do 
do 
17 
6. . 
18 
Died permaturely. 
