36 



REPORT 10.<^, U. S. DEPARTMENT OF AGRICULTURE. 



The young hatch in from 3 



to 



Fig. 46.—Bryobia pratensis: Larva. 

 (Author's illustration.) 



tree. In the spring they crawl out, ascend the trees, and deposit eggs on the openin- 

 foliage. Each female may lay from 5 to 10 eggs a day for a period of 8 to 12 days': 

 ^5 days, and in about 5 days more are adult. A suc- 

 cession of broods is continued throughout the sum- 

 mer, but wet weather is apt to stop or greatly re- 

 tard their development. 



The mites ordinarily move slowly, but when 

 disturbed can run quite rapidly. For the greater 

 part of the time they remain in one pluce, suck- 

 ing the juices from the leaf. In the spring some 

 species attack the buds. Several of our species 

 are very abimdant and destructive. The common 

 greenhouse species, known as the ''red spider," 

 and which also occurs on many outdoor cultivated 

 plants, is T. bimaculatus Harvey (fig. 38). It is 

 probably the T. cucumeris of Boisduval. Specimens 

 of this species often vary greatly in coloration; the 

 members of each colony, however, usually being 

 alike. In the South T. bimaculatus Harvey is com- 

 mon on violets and from them has spread to cotton 

 fields, where in some localities it works consid- 

 erable damage. T. mytilaspidls Riley is abundant on orange leaves in Florida. In 

 this species the abdominal bristles arise from warts or tubercles, and the tarsus has 

 two simple claws. The most abundant species on orange is a yellowish form— T. 

 sexmaculatus Riley. At times it is a very serious pest to orange cul ture. and an article 

 upon it is found in the Report 

 of the Entomologist for 1889. 

 It occurs on the under sur- 

 face of the leaves. The eggs 

 are colorless or pale greenish- 

 yellow. 



T. pratensis Banks is a pale 

 greenish species abundant in 

 some parts of the West on 

 alfalfa and other field crops. 

 T. opuntiss Banks is very in- 

 jurious to the prickly pear 

 cactus in Texas. It is wholly 

 bright red in color. An Euro- 

 pean species, T. gibbosus Can., 

 with very short legs and short 

 hairs on the broad body, has 

 been taken on spruce trees in 

 Canada, but possibly only intro- 

 duced. T. pilosus Can. et Fanz . 

 also occurs in Canada and New 

 Jersey, where it does much dam- 

 age to the leaves of fruit trees. 



In T. b'icolor Banks, a species common on the loaves of oak aiul chestnut, (he tarsus 

 has but one claw. A form occurring on cotton in Louisiana is known as T. glovcri 

 Banks (fig. 44); it is bright red and greatly resembles the common greenliouse species. 

 There are several remedies for red spider. One is to keep the plants moist, spraying 

 them with water once a day. But the best remedy is flowers of sulphur applied either 



Fig. iT.—Stigmadiafloridann.s: Mite, niouth-part.s, and daws. 

 (Author's illusfralion.) 



