. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 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 no
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. 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 Fig. 2.—Larva of the red spi- der. The legs in this sta.^e 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. Feb. 6 6 ii 6 s 9 a. m 9 a. m 1 p. m p. 8 a. m 3 p. m 9 a. m Feb. 16 15 16 16 16 16 16 8 a. m 12m 3 p. m 11 a. m 3 p. m 3 p. m 3 p. m Days. 10 9 10 10 9 8 9 Feb. 20 20 20 20 20 20 21 5 p. 9 a. 4 }>. m. 4p. 9 a. 9 a. 4 p. Days. 5 4 2 3 4 4, 3| 5 6 L3j 7. No. Second molt. Length of stage. Third molt. Length of stag
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