classification and description of common insects ii 9 



Thripid^ (Thrips) 



Grass Thrips (Anaphothrips striatus Osborn).— Feeds by sucking 

 the juices of various grasses such as timothy, Kentucky blue, couch 

 grass and oats. 



Adult. — Small, 3^f g inch long, yellowish or brownish-yellow; four 

 narrow wings fringed with hairs; feet bladder-like; parthenogenetic; 

 May-June. Hibernate. 



Eggs. — First brood laid in spring, hatching in 10 to 15 days; summer 

 eggs hatching in 4 to 7 days. 



Nymphs. — Become full grown in spring in about 2 weeks, summer 

 forms in 4 days. Life-cycle in 12 to 30 days. 



" Thrips injury on the leaves shows as minute dots or lines usually 

 running parallel with the leaf veins and remaining white." 



Pear Thrips {T(Bniothrips inconsequens Uzel). — (Consult Bull. 

 80, Part 4, U. S. Bur. Ent., 1909; Bull. 343, N. Y. Ag. Exp. St., 191 2; Bull. 

 15, Ent. Br. Dept. Ag. Can., 1918.) A pest in central California and 

 British Columbia, along Hudson River and in Pennsylvania to pear, 

 apple, cherry and plum. Chief injuries done by adults to the buds in 

 spring (Fig. 75). 



Adult. — Minute, slender, dark brown, 3^^5 inch long; wings fringe- 

 like and fiat along the back. Enters fruit buds in early spring. One 

 brood a year. 



Eggs. — ^Laid by a sharp, curved, saw-toothed ovipositor beneath 

 epidermis of fruit and leaf stems as the trees come into bloom, causing 

 "bleeding," and giving the bud a shrivelled, scorched appearance when 

 infestation is heavy. 



Nymphs. — Hatch out in blooming time and become full grown in 

 about 2 weeks. They then drop to the ground and form a pupal cell 

 some distance below, where they hibernate. The pupal stage is an 

 inactive stage and lasts about 2 months before the adult appears. 



Control. — Spray early with kerosene emulsion or soap solution, or 

 distillate oil emulsion, to which is added nicotine extract. 



Greenhouse Thrips (Heliothrips hcBmorrhoidalis Bouche). — This in- 

 sect injures the leaves of many greenhouse plants which first become 

 spotted, then blotched and finally wilted. Drops of a reddish fluid, 

 turning black, cover the leaves. (Consult Bull. 64, Pt. 6, Bur. Ent., 

 U. S. Dept. of Agriculture.) 



