32 BULLETIN 416, U. S. DEPARTMENT OF AGRICULTURE. 
ground and 650 feet from the infested orchard. All of these tests 
were made at times when the usual light summer winds were blowing. 
We conducted similar tests at Batesburg and were able to corrob- 
orate to some extent the results of Munger. In one test we suspended 
by a string a board bearing on each side two sheets of sticky fly paper. 
The trap board was then attached to a wire stretched between poles. 
A sticky substance was smeared on the suspending string to prevent 
the mites from reaching the sticky surface by crawling. The sus- 
pended board was free to swing in any direction, so that mites being 
borne by the wind from any direction would be intercepted. An 
orange tree which harbored T'etranychus mytilaspidis stood about 300 
feet from the exposed sticky surface, and several other host plants 
infested with 7. bimaculatus grew within 20 to 25 feet. After an 
exposure of 36 hours the sticky paper was examined. Ten adult 
specimens of 7’. mytilaspidis and several immature individuals of T. 
bimaculatus were caught. 
During the periods of drought and food scarcity mites have been 
seen to seek the highest or terminal points of branches, and this habit 
of the red spider may be closely associated with dispersion by wind. 
Naturally, this act would brmg them to points where the effect of 
the wind would be greatest. 
OTHER DISPERSION AGENCIES. 
Several additional agencies have been suggested by various writers 
as means of spread of the red spider. The operation of cultivating 
the crop has long been considered to be instrumental in conveying 
mites from point to poimt about cotton fields. Titus (1905) main- 
tained that the members of hoe gangs and cultivators are the most 
common means of distribution. He claimed that mites cling to any 
substances that brush against them, and in this manner are rapidly 
and thoroughly scattered over fields. The effect of distribution along 
rows and across fields, following the routes taken by farm hands, can, 
he claims, be traced easily by the resulting infestation along these 
routes. The present writers are inclined to minimize this acci- 
dental type of dissemination. Even when manipulated with the 
finest camel’s-hair brush a certain percentage of imdividuals are 
killed. 
Allied with this form of dispersion is that of accidental transpor- 
tation by larger insects. Titus states that mites have been taken 
from several insects, such as grasshoppers and small Hemiptera, 
which often visit cotton plants. Such agencies of dispersion as in- 
sects, domestic animals, poultry, and wild birds should be considered 
as being of minor importance. 
