70 
should be turned away from the plants for this purpose. They pos- 
sess the advantage of also acting as a stimulant to plant growth. 
Stable manure is apt to induce infestation, as this species is well known 
to develop in excrement and other decomposing material. As soon 
as plants show signs of wilting and maggots are known to be present, 
the injured plants should be promptly pulled and destro^^ed. 
The above methods have been used with success against onion mag- 
gots and similar root-feeding species, and may be all that is required 
in the case of ordinary infestation of beets. 
One of the best remedies for root maggots is bisulphid of carbon. 
It has been used with more or less success by Prof. A. J. Cook and' 
others since 1880. In its application great care should be exercised 
that the liquid shall not come in direct contact with the roots of the 
affected plants. Directions for the treatment of plants affected b}^ 
root maggots are furnished on page 14: of Farmers' Bulletin 145. 
a cop3^ of which can be had upon application to the Secretary of 
Agriculture. 
THE RED SPIDER. 
The common or two-spotted red spider {Tetranychus himacidatus 
Harv.) is usually present in most fields of sugar beet east of the Rocky 
Mountain range, but it is preeminenth" a greenhouse pest, and as a 
rule does comparatively little injur}^ to plants growing out of doors. 
It is unique as a vegetable pest in that it is not a true insect, nor even a 
spider, as the popular term would imply, but a spinning mite. As the 
word mite indicates, these creatures are extremely minute, and are 
frequentl}^ not noticed until the}^ become excessiveh^ numerous, as is 
apt to happen during summer droughts. The}^ do considerable dam- 
age in flower and vegetable gardens, but attain" their greatest destruc- 
tiveness in connection with plants grown under glass. 
The general appearance of the common red spider is shown in figure 
65, highly magnified. The length of a full-grown individual is only 
about one-fiftieth of an inch. The ground color is reddish, usually 
more or less tinged with 3^ellowish or orange, and most individuals 
have a dark spot on each side, due to the food contents of the body. 
The young are similar to the adults, differing in having only three 
pairs of legs, while the adults have four. This red spider spins threads, 
but does not use them for climbing. The threads are frequently so 
numerous as to form a tissue visible at a little distance. Webs are 
usualW constructed on the under sides of leaA'es and within them the 
mites feed and lay their eggs from which the 3^oung develop. 
This red spider is quite likely of foreign origin, but its distribution 
has not been carefully studied. 
It is inclined to be omnivorous, attacking a wide range of jDlants. 
As the red spiders increase in number the leaves of an affected plant 
