THE CADELLE 29 
Table 6. — Duration of the pupal stage of the cadelle — Continued 
No. 
Date 
pupated 
Date 
adult 
emerged 
Length 
of pupal 
period 
Average 
mean 
tempera- 
ture for 
pupal 
period 
26 
1923 
May 1 
6 
9 
9 
13 
15 
27 
June 3 
10 
17 
21 
25 
23 
July 12 
14 
1923 
May 21 
27 
28 
27 
30 
31 
June 8 
15 
23 
26 
July 1 
4 
4 
21 
22 
Days 
20 
21 
19 
18 
17 
16 
12 
12 
13 
9 
10 
9 
11 
9 
8 
R 
73.5 
27 -. 
74 
28 
74.5 
29 - 
74 
30 
76 
31 . :__ 
77 
32 - 
83 
33 - - 
81 
34 
81 
35 --- 
85 
36 ' 
84 
37 
83 
38 
83 
39 
85 
40 
84 
LENGTH OF LIFE CYCLE 
It has been assumed by previous writers that there is but one 
generation of the cadelle each year under favorable conditions. 
These investigations prove that there are often two generations, and 
that there may be a partial third generation a year in the vicinity 
of Washington, D. C, with ample evidence that in a tropical climate 
three generations may normally occur under favorable food con- 
ditions. The shortest developmental period from egg to adult ob- 
served by the writers was 67 days, from June 13 to August 19, 1922, 
when the average mean temperature for the period was 81° F. The 
adult was a female and oviposited for the first time September 18, 
1922, completing a life cycle from egg to egg in 97 days. It is not 
likely that the cycle is ever much shorter than this in the vicinity of 
Washington, and usually it is considerably longer. In Table 7 are 
given data on what are termed by the writers the " short develop- 
mental period," egg to adult, completed during one season of activ- 
ity, as compared with the data in Table 8 covering the much longer 
developmental period, egg to adult, when the insect overwinters as 
a larva. It will be noted that when the developmental period from 
egg to adult is completed during a single season of activity, this 
period varies from a minimum of 67 days to a maximum of 134 
days. With life cycles during which the larva hibernates, the egg- 
to-adult period lasts from 271 to 410 days. When it is realized that 
should the insect be accidentally placed in cold storage with its food 
at temperatures ranging from 40° to 50° F., it will remain inactive 
for well over a year only to resume activity on the removal of its 
food to ordinary trade channels, one can easily appreciate that the 
life cycle is capable of tremendous prolongation. In this connec- 
tion one should not forget the remarkable larvae reported by Mc- 
Colloch (22) that lived 628 to 1,248 days before transforming. 
