THE RED SPIDER ON" THE AVOCADO. 5 
THE EGG. 
The egg (fig. 3, 0, b) is globose in shape, smoky amber in color, and 
bears a stalk at its apex. Guy fibrils are occasionally seen connecting 
the egg with the leaf. 
The eggs are deposited singly and when the leaf first becomes in- 
fested are generally found located along the midrib at the base of the 
leaf. As the activities of the mites increase with succeeding genera- 
tions, the eggs may be found scattered over the entire leaf. 
The incubation period varies according to the temperature and gen- 
eral climatic conditions. (See Table 1.) During midwinter, with 
mean daily temperatures between 60° and 70° F., incubation requires 
from 7 to 11 days. During April and May the incubation period 
averaged from 4 to 5 days with mean temperatures between 70° and 
80° F., in rearing experiments with this species. In hatching, the 
shell of the egg splits more or less completely around and the larva 
easily extricates itself. During the height of the red spider season 
leaves will be observed heavily covered with hatched eggshells which 
adhere to the leaf and impart to it a whitish cast. 
Table 1. — Length of the egg stadium. 
No. 
Date de- 
posited. 
Date 
hatched. 
Dura- 
tion. 
Mean 
temper- 
ature. 
No. 
Date de- 
posited. 
Date 
hatched. 
Dura- 
tion. 
Mean 
temper- 
ature. 
1 
2 
3 
4 
5 
6 
Oct. 15 
Oct. 22 
Nov. 8 
Nov. 30 
Dec. 18 
Jan. 1 
Oct. 20 
Oct. 26 
Nov. 13 
Dec. 8 
Dec. 25 
Jan. 11 
Days. 
5 
5 
8 
7 
10 
o F 
78 
77 
72 
70 
65 
58 
7 
8 
9 
10 
11 
12 
Jan. 21 
Feb. 15 
Mar. 15 
Apr. 1 
Mav 31 
July 11 
Feb. 1 
Feb. 22 
Mar. 20 
Apr. 5 
June 5 
July 15 
Days. 
11 
7 
5 
4 
5 
4 
o F 
60 
70 
72 
75 
76 
79 
THE LARVA. 
The newly hatched larva (fig. 3, c) is round, very light yellow, 
possesses six legs, and in size does not exceed that of the egg from 
which it emerged. It is very delicate, and a marked characteristic 
is its possession of conspicuous carmine eyes. During the process of 
development and feeding the young creatures commence to change 
color. The larva measures 0.17 mm. in length on an average. 
As with practically all mites the larva stage is divided into an 
active and a quiescent period. The former is passed while the larva 
is feeding and the latter in preparation for the first molt. The 
time spent in the quiescent period of the larva stage averages in most 
instances only a few hours. The average length of the larval period 
is 2.58 davs. 
