84 
THE PLUM CUECULIO. 
much, depending upon the character of the weather, whether dry or 
rainy. During periods of drought beetles appear to remain in their 
cells much longer than if the earth be moist or wet, as from rains. 
In fact, in orchards it has often been observed that shortly after a 
good soaking rain beetles were soon in evidence in large numbers, 
whereas previously they had been quite scarce. 
Some data have been collected on the exact time spent in these 
three conditions in the soil and are brought together in the following 
tables. Writers appear not to have investigated this point hereto- 
fore. The data from a practical standpoint are important, since dur- 
ing the pupal stage the insect would be likely to suffer most from 
cultivations. 
Table XLI. — Length of -pupal instar of the plum curculio and days spent in soil as larva, 
pupa, and adult, Washington, D. C, 1908. 
Individual No. 
Date 
larva 
Left 
fruit. 
Date of 
pupation. 
Date of 
transfor- 
mation 
to adult. 
Date 
beetle 
left 
soil. 
Days in 
larval 
stage 
before 
pupa- 
lion. 
Days in 
pupal 
stage. 
Days as 
beetle 
in soil. 
Total 
days in 
soil. 
1 
June 6 
...do 
June 19 
June 18 
June 22 
June 18 
June 19 
June 18 
...do 
June 27 
...do.... 
...do.... 
...do.... 
June 29 
...do.... 
June 27 
June 29 
June 27 
June 29 
...do.... 
July 3 
June 30 
...do.... 
...do.... 
July 1 
June 29 
...do.... 
June 30 
July 1 
June 29 
June 30 
July 5 
July G 
Died. 
July 5 
July 6 
July 8 
July 6 
July 8 
July C 
July 5 
July 6 
Julv 11 
...do.... 
July 7 
...do 
July (i 
July 5 
Julv 8 
Died. 
July 7 
...do.... 
do 
13 
12 
10 
12 
13 
12 
12 
16 
12 
13 
12 
15 
13 
13 
13 
13 
10 
14 
14 
14 
14 
14 
8 
9 
5 
9 
10 
11 
9 
7 
9 
10 
11 
9 
8 
8 
8 
9 
10 
6 
7 
8 
6 
7 
8 
9 
29 
2 
30 
3 
...do 
4 
...do 
8 
7 
9 
9 
9 
9 
6 
8 
11 
7 
5 
6 
9 
29 
5 
...do 
30 
6 
...do.... 
32 
7 
...do 
30 
8 
...do 
June 22 
June 18 
June 19 
June 18 
June 24 
June 22 
...do.... 
...do.... 
...do.... 
June 19 
June 23 
...do.... 
...do 
...do 
32 
9 
...do 
30 
10... 
..do 
29 
11 
...do 
30 
12 
June 9. 
...do 
32 
13 
32 
14 
...do 
28 
15 
16 
17 . 
...do.... 
...do.... 
...do 
28 
27 
26 
18 
...do 
29 
19 
...do.... 
...do 
20 
(> 
8 
7 
28 
21 
...do 
28 
22 
.do... 
...do... 
28 
Total 
290 
184 
155 
587 
13. 18 
8. 30 
7.75 
29. 35 
From the table it will be noted that the average time spent in 
the soil before pupation for the 22 individuals is 13.18 days; the 
length of the pupal instar, 8.36 days; and the period occupied in 
the soil as a beetle before emergence, 7.75 days. The average time 
spent in the ground from entrance of larvse to emergence of adult 
is 29.35 days. 
These larvaB were kept in large glass vials, the soil being a sandy 
loam. Specimens were kept in an out-of-doors breeding cage in 
the insectary yard, at Washington, D. C, where the temperature 
would be somewhat higher than in the soil. 
Mr. Hammar made observations during 1910, at Douglas, Mich., 
on a large series of individuals, as detailed in Table XLII, 
