372 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



and is about half an inch long when grown. The larvae web the 

 flower-heads together until they are contracted into masses of 

 web and excrement ^ as shown in the illustration. " After the 

 larvae have consumed the flowers and unripe seeds and become 

 nearly full grown, they enter the hollow stems of the plant by 

 burrowing their way inside, generally at the axils of the leaves, 

 and then feed upon the soft, white lining of the interior. Here, 

 inside the hollow stem, they change to the pupa state. The 

 larvae are moderately gregarious. They will sometimes eat newly 

 sown parsnips after the older plants originally attacked have 

 been destroyed, in such cases eating the tender green leaves, while 

 of the older plants they eat only the flower-heads and interior 

 lining of the stems." The moths appear in late July and early 

 August. 



Control. Thorough spraying or dusting with arsenicals will 

 destroy the caterpillars, according to Chittenden. If the flowers 

 are destroyed before they are noticed, cut off and burn all infested 

 stems before the moths emerge from the pupae. Obviously it will 

 be important to avoid planting parsnips in or near waste places 

 which have grown up in wild carrot. 



The Onion Thrips * 



The small yellowish "thrips" which chafe the epidermis from 

 the green leaves, causing them to dry out, whiten and die, have 

 become well known to onion growers in practically all parts of 

 the United States where onions are raised extensively. It is a 

 European insect, occurring in Germany and Russia, and has also 

 been imported into the Bermudas. 



The adult thrips is about one-twenty-fifth of an inch long, of 

 a pale yellow color, tinged with blackish. The general appear- 

 ance, much enlarged, is shown in Fig. 314. The slender, elongate 

 body bears two pairs of narrow, bristle-like wings which are of 

 no value for flight. The fore-wing contains two-wing-veins, and 

 the hind-wing but one, the posterior margin of both bearing a 



* Thrips tabati Lind. Order Thysanoptera. See Quaintance, A. L., 

 Bulletin 46, Fla. Agr. Exp. Sta., "The Strawberry Thrips and the Onion 

 Thrips." Full account and Bibliography; Pergande, Th., "Insect Life," 

 Vol. VII, pp. 292-295; Osborne-Mally, Bulletin 27, Iowa Agr. Exp. Sta., 

 p. 137-142; Sirrine, Bulletin 83, N. Y. Agr. Exp. Sta., pp. 680-683, Farmers' 

 "etin 1007, U. S. D. A. 



