io The Colorado Experiment Station. 
of legs are much shorter, as is shown in the figures. When the 
mites are seen with the aid of a glass, upon the surface of a leaf, 
the legs appear much shorter than they do in the drawing, for the 
reason that they are not extended to their full length while the 
mites are feeding, or while at rest, while those of the brown mite are 
nearly always extended to their full length. A glance through any 
ordinary hand lens is all that is necessary to be able to distinguish 
the brown mite from the red spider, because of this characteristic. 
When first hatched this species of red spider is light green, with 
small dark colored spots on the back. Later the color may change 
from a light green to a deep brown, or a bright red. Owing to 
the variability of color this character cannot be depended upon at 
all in the identification of the species. The spots also vary in size 
and placing on different individuals. Generation after generation 
of the mites appear during the summer months, and at all times of 
the season there may be found eggs, and all other stages of the 
mites upon the leaves. 
The winter is spent in the ground, and here we have an im¬ 
portant difference in the life history of the two species treated in 
this bulletin. On August 9th, myriads of red mites were found in 
the ground at the crowns of trees upon which they had been feed¬ 
ing. At this time they were all red in color. Although most of 
them occurred close to the trunks of trees, some were found at a 
distance of 10 feet away, where they had crawled beneath clods of 
soil undoubtedly to remain over winter. It is probable that out of 
the large numbers that leave the foliage and enter hibernation quar¬ 
ters only a very few survive the winter. I11 the early spring, when 
the foliage begins to grow, these few crawl out of their winter 
quarters, ascend the trunks of trees and deposit their eggs for the 
perpetuation of the species. On last April 7th a number of these 
mites were found trapped in a “Tree Tanglefoot” band, which had 
been applied to the trunk ol an apple tree to catch the migrating 
woolly aphids which wintered in the ground. 
Nature and Appearance of Their Injury .—The injury from 
this species is similar to that of the brown mite. The leaves of an 
infested tree are often yellow in spots, which present a blister-like 
appearance. This condition has not been observed with brown 
mite injury, and is due to the red spiders spinning their webs over 
certain small areas of the leaves, and feeding within those areas. 
The webs are always found on leaves injured by red spider, and 
when the orchardist finds these webs he can rest assured that he 
has red spider to contend with, as the brown mite does not have the 
power of spinning a web. 
Trees and Plants Infested .—In every case, mite injury to shade 
trees observed the past season, was due to this species of red spider, 
and not to the brown mite. It has been observed on the same fruit 
