LIFE HISTORY. 
11 
THE LARVA AND NYMPH. 
Descriptive. — The larva (fig. 2) is a minute, almost globular object, 
and differs from the adult in the possession of only three pairs of legs. 
This six-legged condition lasts only during the first stage, i. e., until 
the first molt, from which the mites emerge as nymphs, with four 
pairs of legs, and, except for size and the maturity of the sexual 
organs, similar to the adults. According to C. H. Perkins, 1 the sex- 
ual organs appear with the second molt, but copulation does not take 
place until after the third. 
Length of stages. — The length of the larval 
and nymphal periods varies, being from 8 to 16 
days, according to the prevailing temperature. 
As shown in Table I, this period under the 
temperature conditions given in the plat was 
15 to 16 days. During May, however, this 
period was found to be 11 to 12 days and in 
July, 1911, which was an exceptionally warm 
month, two mites were observed to be mature 
8 days after emerging from the egg. 
Under field conditions in 1911 it was impos- 
sible to carry out any very extensive life-history experiments. During 
the winter, however, a series was carried out in the insectary of the 
University of California, at Berkeley, Cal. 
This series is recorded in Table I. 
Fig. 2.— Larva of the red spi- 
der. The legs in this stage 
are transparent. Greatly en- 
larged. (Original.) 
Table I. — Transformations and length of stages of 
the red spider in California 
, 1912. 
No. 
Eggs laid. 
Hatched. 
Length 
of stage. 
First molt. 
Length 
Date. 
Time. 
Date. 
Time. 
Date. 
Time. 
of stage. 
1 
2 
3 
4 
5 
6 
7 
Feb. 6 
6 
6 
6 
8 
9 a. m 
9 a. m 
1 p. m 
3.30 p. m.. 
8 a. m 
3 p. m 
9 a. m 
Feb. 16 
15 
18 
16 
16 
16 
16 
8 a. m 
12m 
3p. m 
11 a. m 
3 p. m 
3p. m 
3 p. m 
Days. 
10 
9 
10 
10 
9 
8 
9 
Feb. 20 
20 
20 
20 
20 
20 
21 
5 p. m. . 
9 a. m. . . 
4p.m.. 
4p. m... 
9 a. m. .. 
9 a. m. . . 
4 p. m... 
Days. 
5 
4 
4* 
31 
13| 
5 
No. 
Second molt. 
Length 
of stage. 
Third molt. 
Length 
of stage. 
First egg laid. 
Total 
time, egg 
to adult. 
Date. 
Time. 
Date. 
Time. 
Date. 
Time. 
1 
2 
3 
4 
5 
6 
7 
Feb. 25 
25 
25 
25 
25 
4 p. m... 
4 p. m... 
4 p. m... 
4 p. m... 
4p. m... 
Days. 
5 
P 
5 
5§ 
5 
4 
Feb. 29 
29 
29 
29 
9 a. m 
9 a. m 
9 a. m 
9 a. m 
Days. 
3§ 
3§ 
Mar. 2 
2 
11 a. m.. 
11 a. m.. 
Days. 
25 
25 
2 
2 
2 
3 
11 a. m.. 
11 a. m.. 
11 a. m.. 
11 a. m.. 
25 
24 
2 
2 
5 
5 
9 a. m. 
4 p. m. 
29 
Mar. 1 
9 a. m 
11 a. m 
4 
it- 
23 
25 
Report of the Vermont Agricultural Experiment Station, 1896-97. 
