JOURNAL OF ENTOMOLOGY AND ZOOLOGY 59 
rest. Experiments have shown that when the temperature is 
about 89 it travels two or three times as fast as when the tem- 
perature is 65. On the whole if it was left to travel by itself 
the distribution would be very slow. 
Very little is said about the parasite of this scale in Cali- 
fornia, but where fumigation and spray have never been used as 
high as 40 per cent. of the scale has been parasitised. 
This article shows how necessary it is to keep the quarantine 
as rigid as possible and keep on the lookout for a parasite that 
will not injure the trees. 
C. A. Perrin. 
THE RED SPIDERS AND MITES OF CITRUS TREES 
H. J. QUALE 
College of Agr. Univ. of Cal., Publications. 
The two most important species to the citrus growers in Cali- 
fornia are the red spider and the six-spotted mite. Both species 
were introduced into California from Florida, the first in 1890, 
the last in the late eighties. 
These animals live and breed entirely upon the trees and are 
only incidentally found on the ground. They are most abundant 
during May and June but are sometimes abundant at other 
seasons. When in small numbers they are not noticed but that is 
the time to get control of them. 
The red spider (Zetranchus mytilaspidis) is the worst pest 
and is the most widely distributed. It is against this species 
that most of the control work is directed. This species is told 
from the other by its red color and the fact that the bristles 
over the body arise from prominent tubercles. The eggs are 
told by the guy threads which radiate from vertical stalks. 
The six-spotted mite (7. sexmaculatu) is slightly smaller 
than the red species. It is never red in color. The eggs are 
white or yellow and perfectly spherical. 
The control of these species is not difficult or expensive if 
handled in the proper way at the proper time. Fumigation has 
