INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



13 



THE RED SPIDER 6 

 Bryobia pratensis Garman (Family Tetranyehidse) 



(Figs. 14, 15) 



Description. — The young mites are red, becoming brown when fully 

 developed. Though very much smaller than a pinhead, this species 

 is much larger than any of the common so-called "red spiders" in the 

 State. The eggs are red, globular and so small as to be scarcely visible 

 to the unaided eye (Fig. 14). This species is easily distinguished by 

 the small marginal plates around the edges of the body, which may 

 be seen under a compound microscope, as shown in Fig. 15. 



Life History. — The eggs, deposited in the fall, hatch with the first 

 warm weather in the spring and the mites at once begin to work. 

 Their development is very rapid and power of reproduction exceed- 

 ingly great, so by summer there are often sufficient numbers to do 



Fig. 14. — Eggs of the red spider, Bryobia pratensis Garman, on almond twigs. 

 Greatly enlarged. (Original) 



much damage. Breeding and feeding continue until fall, when the 

 over-wintering eggs are laid and operations suspended until these 

 hatch in the following spring. 



This species is also known as the brown, clover and almond mite. 



