The Geographical Distribution of Our 



Common Red Spider, Tetranychus 



Telarius Linn 



H. E. EWING 



corvallis, oregon 



Introduction 



Our commou red spider, Tetranychus telarius Linn., is appar- 

 ently an introduced pest. In Europe it has been known to science 

 for over a century and a half, where it not only is found on 

 many cultivated plants, but also is found on many wild, or native 

 ones. Hence it is very proljable that Europe is the native home 

 of this alien mite. 



Just when this pest was first introduced into this country we 

 do not know, but probably at a very early date on greenhouse 

 l^lants. In 1855 Glover reported a red spider from cotton which 

 was doing considerable injury. The species was very probably no 

 other than the cotton red spider of today, which we should regard 

 as T. telarius Linn. In 1869 Shinier made reference to a red 

 spider, but probably he was considering a different species. 

 Saunders in 1880 refers to this species, but does not give us an 

 extensive account of it. 



In working out the distribution of this mite pest in the United 

 States, I have not only consulted the literature relative to the 

 red spiders, but I have also written many letters to entomolo- 

 gists, and specialists in the Acarina, have collected specimens in 

 some dozen different states, and have examined slides in several 

 educational institutions. I am especially under obligations to 

 Prof. H. J. Quayle of the University of California for many 

 sjjecimens from the citrus regions, and to Dr. Nathan Banks 

 for the privilege of examining some of his specimens of red 

 spiders, and for getting the many records which he has obtained 

 of the occurrence of the species in this country. 



