32 



BULLETIN 911, U. S. DEPARTMENT OF AGRICULTURE. 



Cocooning began as early as August 15 and continued until 

 October 31. 



PERCENTAGE OF COCOONING PREVIOUS TO AND DURING GRAPE 



HARVEST. 



Table XXXVI. — Percentage of cocooning previous to and during grape harvest, San- 

 dusky, Ohio, 1918. 



Time. 



Date. 



Number 



of 

 cocoons. 



Percent- 

 age of 

 total. 



Previous to beginning of Concord harvest. 



During Concord harvest 



Previous to end of Concord harvest 



Previous to beginning of Catawba harvest 



Previous to end of Catawba harvest 



After Catawba harvest — 



To Sept. 20...... 



Sept. 20-Oct. 10. 



To Oct. 10 



To Oct. 8 



To Oct. 26 



To Nov. 1 



343 

 342 

 685 

 670 

 821 

 21 



40.73 

 40.62 

 81.35 

 79.57 

 97.50 

 2.50 



The data in Table XXXV are summarized in Table XXXVI and 

 emphasize similar records for the seasons of 1916 and 1917. From 

 these records of three seasons involving a large quantity of larvae 

 regularly collected it must be concluded that a very large part of the 

 second-brood larva? leave the fruit previous to and during the early 

 part of grape harvest. 



MISCELLANEOUS RECORDS. 



In the course of the life-history studies some observations were 

 made that have a bearing on the habits of the insect and the develop- 

 ment of the different stages. 



ADULT. 



The pupa? formed in the fall of 1916, from which moths emerged in 

 the spring of 1917, were kept through the spring emergence period of 

 1918 to determine if any pupse lived over and emerged the second 

 spring. No moths emerged from this material the second year. 



In an effort to approach natural conditions for moths in confine- 

 ment dilute strained honey was supplied in the rearing jars. The 

 usual observation was that the moths were not attracted to the food, 

 but would feed if they came in contact with it. In one case when no 

 new food had been supplied for six days, upon placing water on the 

 sand in the bottom of the cage two moths immediately went \\ inches 

 to the water and appeared to drink of it. 



The adults seldom are seen in the vineyards during the day, and 

 throughout these investigations, though the writer was in heavily 

 infested vineyards almost daily, moths were rarely observed. In 

 one case a moth was seen resting on a young cluster of grape buds, 

 another was observed on the upper side of a grape leaf, and a third 

 adult was seen in flight about the lower part of a grapevine. It 

 alighted on a cane, ran into the angle of a small stub on the cane, 

 and rested there, its head in the angle. 



