THE RED SPIDER ON COTTON. 5 
winter Gn the Southeast) and it is usually an easy matter to find red 
spiders actively feeding on these leaves. Such occurrences give rise 
to the opinion that much of the infestation in rural localities arises 
from the wild blackberry. 
Several early vernal plants or weeds (escapes) play an important 
role in the seasonal development and spread of the red spider. The 
more important of these are hedge nettle (Stachys arvensis), wild 
geranium (Geramum carolinianum), sow thistle (Sonchus asper), 
evening primrose (Oenothera lacvmata), sunflower (/Telianthus annuus), 
and vetch (Vicia sativa). Durmg March and April these plants are 
usually to be found in beds and borders in sheltered positions and the 
seasonal development of the red spider progresses faster than else- 
where, owing to the higher temperatures which obtain in these loca- 
tions. Such beds are prolific dispersion sources. 
Garden beans are also important hosts, and throughout a July, 
and August are seldom free from mites, at times becoming so heavily 
infested that their color turns yellow and many of the leaves fall. 
They are thus a constant menace to surrounding crops. 
Tomato vines are known to afford an opportune shelter for mites, 
and after the abundant appearance of enemies of the red spider, at 
a time when other infested plants have become cleared of mites, 
tomato leaves may usually be found to harbor large numbers. This 
doubtless comes about through the fact that tomato vines rarely 
support enemies of the red spider. Hence they serve to harbor the 
mites during periods of heavy mortality until the time arrives when 
the latter may spread with impunity to other hosts. 
Since 1855, when Glover reported injury to cotton by a red spider, 
Prof. H. A. Morgan (1897), Mr. E.S. G. Titus (1905, a, b), and other 
investigators have published on the damage to cotton by this pest. 
As indicating the very general occurrence of the mite on cotton, it 
is of interest that in the course of visits to many points in sections 
of every cotton State, the common red spider was found in every 
single locality. The majority of these records on cotton concern 
very light outbreaks. 
LIFE-HISTORY SUMMARY. 
The eggs of the red spider are deposited on the under surface of 
leaves of a great variety of plants. The eggs hatch in a few days 
and the 6-legged larve at once begin to feed by inserting their sharp 
probosces into the tissue of the leaf. The larval activities are con- 
fined to the immediate region of birth, and the larve soon molt into 
8-legged nymphs. Females require two nymphal stages before becom- 
ing adult, while males require only a single nymphal stage between the 
larva and the adult. The female protonymph, like the larva, after 
a period about equal to that required by the latter, molts to the sec- 
