RED SPIDER ON COTTON. 5 
11 days for the completion of a generation. In an average season 
at Batesburg, S. C., there are 17 generations of red spiders. 
In developing from the egg to the adult stage the red spider 
follows one or the other of two distinct courses, depending on the 
sex. With the female, the egg hatches in about four days to a tiny, 
colorless, 6-legged form known as a larva, which feeds eagerly, and 
in about two days in summer time sheds its skin and becomes an 
8-legged form called the primary nymph. The latter feeds in a 
manner very similar to that of the larva, and becomes greenish or 
yellowish in color with conspicuous blotches at the sides. At Bates- 
burg this stage requires a trifle over two days for completion, when 
the skin is again shed and the secondary nymph appears. The 
Fic. 5.—A severe example of red-spider work in a cotton field. Nearly all plants in the 
foreground are in the condition shown in figure 4. The source in this case was certain 
pokeweed stalks growing in the weed border seen in the upper right-hand corner of the 
figure. (Author’s illustration.) 
latter lives about as the preceding stages do and becomes more 
nearly the size and color of the adult. After about one and nine- 
tenths days another molt or skin shedding occurs which gives origin 
to the adult female. Thus, for the most favorable season, the 
females require about nine days to mature. 
The development of the male is very similar to that of the female 
with the difference that the second nymphal stage is lacking. The 
other stages, however, are slightly lengthened, so that the male red 
spiders usually complete their development only one day sooner than 
do the females. . 
In establishing herself upon cotton the female selects a concave 
area between the under veins of the leaf and, after a brief feeding 
