THE RED SPIDER ON COTTON. 3 



the host plant and upon locality, the general color of the red spider 

 is subject to great variation. 



The eggs are very minute, but in proportion to the mites they are 

 large. They are perfectly round, and when first laid are as clear as 

 water. Each female lays (in the months of June, July, and August) 

 about 50 to 60 eggs, although her brood may in cases exceed 100. 

 Usually about 6 eggs are deposited per da}^ for a period of 9 or 10 

 davs. Less than 3 eggs or more than 10 are rarely deposited in one 

 day in summer weather. During the warmer months the eggs hatch 

 in about 4 days after being laid. 



The newly hatched red spider, called the larva, is almost round, 

 has six legs, and is nearly colorless. It begins feeding at once, and 

 (in summer time) after two days' activity it IJecomes quiet, darkens 

 in color, casts its skin for the first time, and emerges as the primary 

 nymph Avith an added pair of legs — making eight. 



The primary nymph becomes larger in size and darker in color, 

 but gives no indication of sex. Feeding continues actively, and at the 

 termination of another two-day period (in summer months) a second 

 molting occurs, which gives rise to the third stage — the secondary 

 nymph. 



With this last nymphal stage the first indication of sex apj^ears. 

 As with the preceding stages, two days usually suffice in summer 

 for the completion of this period, at the end of which time the 

 skin is shed for the third time and at last the perfectly develoi^ed 

 adult mites appear. At the occurrence of each molt the skin splits in 

 two, crosswise, and the creature crawls out of the two halves. The 

 old cast skins are usually to be seen in abundance among the fibrils 

 of the web. 



THE ADULT MALES AND FE:N[ALES COMPARED. 



Concerning the relative abundance of females and males it may be 

 said that there seems to be a predominance of females throughout 

 the summer, but toward the approach of cold weather the occurrence 

 of the sexes becomes more nearly equal. The period of life of the 

 adult female varies from IT days in midsummer to several months 

 in winter. The male is shorter lived. As before stated, the female 

 is decidedly larger than the male, more rounded behind, and of a 

 much deeper color. She does not move about much, and when she 

 does her motion is rather slow. On the other hand, when not mating, 

 the male is frequently seen moving rapidly about. The body and 

 legs are well beset with bristles, which are somewhat more con- 

 spicuous in the males than in the females. In addition, the legs of 

 the male are longer in proportion to the body than are those of the 

 female. The legs of the first pair are especially long in the male, and 

 are doubtless adapted for clasping. The eyes, consisting each of two 

 orbs, one close behind the other, are situated near the front edge of 

 the body directly over the second pair of legs. 



