Trombidiformes 219 



(McGregor) is one of the major pests of citrus in California. Although 

 found in Florida, it is of little importance there, perhaps owing to cli- 

 matic differences. 



Tetranychus bimaculatus Harvey (also known as T, telarius L.) 

 occurs throughout the country and is a major pest of cotton in the 

 southeastern United States as well as a pest of fruit trees and truck 

 crops throughout the country. 



Bryobia praetiosa (Koch) is a pest of crops in the United States, 

 being serious on almonds, peach, prune, alfalfa, clover, and peas. This 

 species overwinters in the north in the egg stage and in southern re- 

 gions as adults on clover and other plants. It is common in Europe. 



The Tetranychidae are not usually host specific, and on citrus, as 

 well as on other plants, there are several species on the one plant. 

 Tetranychus lewisi McGregor, T. yumensis McGregor, Metatetrany- 

 chiis citri (McGregor), and Eutetranychus clarki McGregor are all to 

 be found on citrus. 



References: 



Blauvelt, W. E. 1945. The internal morphology of the common red spider 

 • mite {Tetranychus telarius Linn.) N. Y. (Cornell) Agr. Expt. Sta. 



Mem. 270. 

 Cagle, L. R. 1949. Life history of the two-spotted spider mite. Virginia 



Agr. Expt. Sta. Tech. Bull. 113. 

 Garman, P. 1940. Tetranychidae of Connecticut. Conn. (State) Agr. Expt. 



Sta. Bull. 431. 

 ., and J. F, Townsend. 1938. The European red mite and its control. 



Conn. (State) Agr. Expt. Sta. Bull. 418. 

 Geijskes, D. C. 1939. Beitrage zur Kenntnis der Europaischen Spinnmilben 



(Acari, Tetranychidae) , mit Besonderer Berucksichtigung der Nieder- 



landischen Arten. Mededeelingen van de Landbouwhoogeschool 



42(4). 

 Grandjean, F. 1948. Quelques caracteres des Tetranyques. Bull, du Mus. 



Ser. 2, 20(6):517-524. 

 McGregor, E. A. 1950. Mites of the family Tetranychidae. Amer. Mid. 



Nat. 44(2):257-420. 

 ., and F. L. McDonough. 1917. The red spider on cotton. U.S. Dept. 



Agr. Bull. 416. 

 Moskovetz, S. N. 1940. Plant virus diseases and their control. Trans. Conf. 



on Plant Virus Disease. Moscow 4-7/11. Moscow, Inst. MikrobioJ. 



Izd. Akad. Nauk U.S.S.R. 1941. 

 Newcomer, E. L, and M. A. Yothers. 1929. Biology of the European red 



mite in the Pacific Northwest. U. S. Dept. Agr. Tech. Bull. 89, 



