24 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. xxvni. 



Two eoinmori P^uropean gcneni, CulfgoKU.'i and Rdpldijuatlius.^ have 

 not been found in this country. The}^ are ver}' .small and of a bright 

 red color. \\\ the genus ^ryrv^/V^ we have but one species, B, 2)rcc- 

 te/isis Garnian, known as the clover-niite. It is very abundant in 

 many localities. In tlie West it is injurious to fruit trees; in the East 



i f 



FK;. 27. — TKTKANYCHrS, MANDIBCLAR PLATE, DORSAL AND LATERAL VIEWS. «, PLATE; b, STYLET; C, 



spina; d, PALPrS. 



it more commonly ali'ects clover and annual plants. The eggs are laid 

 in the autunui in great numbers, attached to the ])ranches and tsvigs 

 of trees. They are red, verv small, and round, and are often mis- 

 taken for the eggs of plant-lice. The adults in the autumn often seek 

 winter (quarters in houses and may l)ecome a great nuisance. Both 



the mites and their ej^gs 

 can be killed by a spray of 

 kerosene emulsion. 



In Teironijchtix the body 

 is subpyriform, and pro- 

 vided above with about 

 twenty-four to thirty-six 

 bristles arranged in four 

 rows. The species of this 

 genus can spin a thread, 

 which, when they are very 

 abundant, becomes a dense 

 mesh or web, visible at a 

 considerable distance. The 

 s])inning organ is not definitely located, but the thread arises from or 

 near the genital or anal opening. The web does not appear to afford 

 the mites any protection, but at times seems to serve to hold the eggs 

 in place. It may l)e either on the upper or lower surface of the leaf. 

 The mites are supposed to hibernate under or among fallen leaves, in 

 the spring ascending trees to start new colonies. 



Fig. 28.— Tetranychi's, cephalothorax kr(i.m above, a, 



palpus; 5, MAXliIBrLAK PLATE; r, KRONTAL BRISTLE; (I, 

 .SUBFRONTAL BRISTLE; ^ EYES. 



