24 BULLETIN 416, U. S. DEPARTMENT OF AGRICULTURE. 
several species of plants then bearing green leaves. Ewing (1914) 
states that in Oregon the females enter the period of hibernation in 
October, and that males are not found during winter. 
At Batesburg we have repeatedly investigated hibernation. Old 
cotton stalks, trash from in and around recently infested cotton fields, 
dormant weed stalks, violet roots and crowns, and similar material 
(gathered from localities of recent infestation) were collected during 
winter and placed in a large Berlese apparatus. The results were 
always negative. Many examinations have been made of dormant 
cotton stalks and other plants which had, during the previous season, 
harbored mites. We have never recovered living red spiders from 
these dormant hosts. In short, there is absolutely no evidence which 
would lead to the belief that hibernation occurs in South Carolina. 
The pest maintains itself throughout the winter on several species of 
wild and dooryard plants. We have traced infestation through four 
successive years, from the primary sources to cotton fields and back 
to the wintering hosts, and have established the botanical sequence 
which constitutes the successive migratory steps of seasonal activities. 
The dispersion of the pest is determined largely by the nature and 
location of the plants upon which the mites overwinter. These hosts 
are divisible into summer hosts and winter hosts. Under summer 
hosts we place such species as harbor mites through the summer and 
which remain green throughout the winter, thus furnishing continu- 
ous feeding during all months of the year. Hosts of this kind are of 
vast importance in that they obviate the necessity of fall migration 
on the part of the mites. Among the more important plants of this 
type are the cultivated violet, strawberry, hollyhock, mustard, privet, 
and grass (Panicum scoparium). It is probably true that compara- 
tively few infestations in cotton arise directly from these summer 
hosts. The balance of the mites persist through winter on the winter 
hosts. These include the native weed species which germinate or 
put out basai leaves in the fall, and to which a certain percentage of 
the migrants, from cotton and other annual plants, disperse. Where- 
ever these weeds are allowed to grow in great profusion they are 
usually found to be infested, and when occupying positions close to 
cotton fields they constitute centers of direct invasion. Among the 
more common of the winter hosts in South Carolina are Stachys 
arvensis, Geranium carolinianum, Rubus sp. Gwild blackberry), Cheno- 
podium botrys, Sonchus asper, and Oenotheralaciniata. Since the great 
mass of red spiders pass the winter on the wild plants, it is evident 
that these plants are of great importance. They occur commonly in 
dense borders along ditch banks, in field borders adjoining areas 
planted to cotton, in dooryards, and bordering roadsides. 
Practically all of the winter hosts possess only prostrate leaves 
during the late fall and winter. This makes the foliage more acces- 
