410 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



is a narrow green stripe, which is bordered on either side by a 

 wider greenish-white stripe. The head is dark straw color, 

 mottled with darker, often purplish dots. The species is widely 

 distributed, occurring in practically all parts of the United States, 

 and may be readily introduced into greenhouses upon plants. 

 Life History. The eggs are very much flattened, translucent, 

 broadly oval disks about one thirty-second inch long, laid in clus- 

 ters of from eight to twelve, several often overlapping. The eggs 

 hatch in from five to twenty days, according to the temperature. 

 The larva* feed mostly at night and becorco full grown in from 



FIG. 296. The celery leaf-tyer (Phlyctcenia rubigalis Hbn.): a, moth; b, 

 same in natural position at rest; c, egg mass; d, larva from above; e, 

 same from side; /, head of same; g, pupa case; h, chrysalis one-half 

 larger than natural size except c, which is twice natural size, and /, 

 more enlarged. (After Chittenden, U. S. Dept. Agr.) 



three to five weeks. They transform to pupae within the webs 

 which they have formed between the leaves, and the moths 

 emerge one or two weeks later. The number of generations 

 which occur out of doors and the method of hibernation have not 

 been determined, but there are probably at least three generations 

 in the open, while the number in greenhouses will depend upon 

 the temperature and the food available. 



Control. Xo very thorough experiments in the practical con- 

 trol of the pest on field crops seem to have been made. A thorough 

 application of arsenate of lead as soon as the young larva? are 

 noticed and before they have webbed the foliage badly would 



