10 
BULLETIN 124, U. S. DEPARTMENT OF AGRICULTURE. 
PUPA. 
The pupa (fig. 6) is yellowish green, with a conspicuous row of 
black clots just within the margin of each wing pad and three black 
dots on each side of the abdomen. It is free, having no cocoon, and 
is found, head up, attached closely by the posterior end to an alfalfa 
stalk or other support, with the anterior end hang- 
ing loosely in a threadlike swing which is joined to 
the same support. 
LIFE HISTORY AND HABITS. 
The complete life cycle for this insect averages 
about 38 days for all generations, the minimum 
length being about 26 days for the third brood and 
the maximum 61 days for the first brood. (See 
Table III.) The time occupied by the different 
stages is as follows: Egg, 6 days; larva, 24 days; 
pupa, 7 days, and a resting and feeding period of 
1 day following emergence of adults during which 
copulation takes place. Males usually complete the 
developmental period several days sooner than the 
females, and thus pass a longer period between 
emergence and copulation. Mr. W. H. Larrimer, working at Nash- 
ville, Tenn., made some interesting records on the life-cycle periods, 
as shown in Table I. It will be noted that these records were all 
made during the months of June and July and correspond with the 
tables for Arizona showing records made during weather of medium 
temperature. 
Fig. 6. — The alfalfa 
caterpillar : Chrys- 
alis, or pupa. 
(Author's illustra- 
tion.) 
Table I. — -Rearing records for the alfalfa caterpillar, Nashville. Tenn., 1913. 
Egg laid. 
Egg 
hatched. 
Egg 
stage. 
Larva 
pupated. 
Larval 
stage. 
Adult 
emerged. 
Pupal 
stage. 
Food plant. 
Days. 
Days. 
Davs. 
June 4 1 
June 7 
3 
June 26 
19 
Julv 2 
"16 
Medicago sativa. 
4i 
7 
3 
July 1 
24 
8 
7 
Do. 
4 
7 
3 
3 
26 
10 
7 
Do. 
27 
30 
3 
16 
16 
23 
7 
Do. 
27 
30 
3 
16 
16 
23 
7 
Do. 
July 2i 
July 5 
3 
22 
17 
29 
7 
Do. 
2i 
5 
3 
23 
18 
29 
6 
Do. 
2i 
5 
3 
28 
23 
Aug. 1 
5 
Do. 
91 
5 
3 
30 
25 
6 
7 
Do. 
16i 
19 
3 
Aug. 2 
14 
8 
6 
Trifoiium hyhridum. 
27 
30 
3 
13 
14 
20 
7 
Trifolium repens. 
27 
30 
3 
14 
15 
21 
6 
Do. 
27 
30 
3 
11 
12 
17 
6 
Vicia sativa. 
27 
30 
3 
12 
13 
17 
5 
Do. 
27 
30 
3 
11 
12 
17 
6 
Do. 
27 
30 
3 
15 
16 
21 
6 
Pisum sativum. 
27 
30 
3 
15 
21 
21 
6 
Glycine hispida. 
1 
4 
3 
July 28 
24 
2 
6 
Trifolium pra tense. 
1 Reared under same conditions of light, moisture, temperature, and food supply. 
Days. 
Average length of egg stage. 3 
Average length of larval stage 18 
Average length of pupal stage 6 J 
