December, ’18] DAVIDSON: CALIFORNIA PISTOL CASE BEARER 
451 
examined May 10, there were 9 living larvae, 12 dead or inactive larvae, 
23 pupae, and 3 parasitized. On May 20, a lot of 59 cases was taken 
from prune and cherry; these consisted of 8 inactive larvae, 1 dead 
larva, 43 pupae, and 7 parasitized. On May 24, only pupae were col¬ 
lected, and a few early moths were observed. 
Observations made in the years 1910, 1911 and 1916 indicated sim¬ 
ilar dates for pupation. 
« Therefore it can be said that the larvae commence their spring feed¬ 
ing as early as the middle of February and as late as the beginning of 
April, and that the majority begin to feed before March 15, that the 
period of pupation extends from the middle of April to the third week 
in May, and that the majority of the larvae transform before the second 
week of May. 
Unless while moving about, the larvae contrive to anchor themselves 
to the plant surface by threads. Notwithstanding the presence of the 
case they are able to move with considerable agility when they so 
desire. 
Position of Pupce on Tree. (PL 15, fig. 2). On apricot the larvae spin 
up chiefly on the leaves, being about equally partial to either surface; 
and to a much lesser extent on petioles and twigs. O.n prune and 
cherries the favorite location chosen is on the upper surface of the 
leaf at about the middle of the midrib, the case being attached to the 
rib; but a few individuals settle on petioles and twigs and a very small 
number dispose themselves on the under surface of the leaves and on 
the upper surface other than at the favored midrib location. As is 
the case with the feeding larva, the case projects from the plant surface 
at a right angle, whereas the cases of the hibernating larvae often lie 
parallel to the surface of bark to which they are fastened. 
Pupal Stage. The duration of the pupal stage varies with tempera¬ 
ture and environment. Normally the pupa case is on the upper side 
of a leaf and receives much direct sunlight, and pupae kept in close con¬ 
finement or in shady quarters develop more slowly than those in nat¬ 
ural conditions. 
The following table indicates records of the pupal stage in 1910. 
Table II. Pupal Stage, San Jose, California, 1910 
No. Individuals 
Date of Pupation 
Date of 
Emergence 
Pupal Stage, 
Days 
Av. Mean 
Temperature 
3 
May 8 
June 1 
24 . 
64.2 
4 
9 
1 
23 
64.4 
1 
9 
2 
24 
64.3 
2 
9 
3 
25 
64.2 
1 
15 
16 
32 
62.8 
1 
19 
16 
28 
62.4 
The average for the 12 individuals was 24.8 days. 
