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 fuiuii^ation and spray have never been used as 

 high as 40 per i-ent. of the scale has been parasitised. 



This article shows how necessary it is to keep the quarantine 

 as rigid as possible and keej) on the lookout for a parasite tliat 

 will not injure the trees. 



C. A. Per rill. 



THE EED SPIDERS AND MITES OF CITRUS TREES 



H. J. QUALE 



College of Agr. I'niv. 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 {Tetraiichns iiiijfilaspidis) 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 (T. sexmaculatii) 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 



