110 Bulletin 223. 



brood is also comparatively small. In a vineyard badly infested in 

 1903, we found in June the next year not more than two or'three cat- 

 erpillars on a vine and many vines had no infested clusters. Three 

 caterpillars were found in one cluster, and sometimes from one-third 

 to one-half of the recently set berries on a cluster were destroyed by 

 a single caterpillar. The smallness of the spring brood is due largely 

 to the efficient work of the many parasitic enemies of the insect the 

 preceding year, doubtless aided often by unfavorable winter con- 

 ditions. 



We have never seen the spring brood of caterpillars feeding any- 

 where except on the grape clusters, but the leaves and tendrils have 

 been recorded in their menu at this time. In a few instances we have 

 found where the caterpillars had burrowed into the fruit stem causing 

 the end of the cluster to die, but their usual menu in June consists of 

 the blossoms and young grape-berries. The caterpillars of the Euro- 

 pean grape-berry moth have similar feeding habits in the spring. 



It is an important fact that the first or spring brood of the cater- 

 pillars do not live inside the small blossoms and berries, but feed 

 openly on the outside. For this offers a vulnerable point for effec- 

 tively attacking the insect with a poison spray, as our experiments 

 have shown. 



By July 1 many of the caterpillars have attained their full size. 

 They go onto the leaves where they make their peculiar cocoons, as 

 shown in Fig. 22. A little flap is cut from the leaf and gradually 

 pulled over and down and fastened to the leaf by silken threads. 

 The inside is then lined with white silk, thus forming a snug cocoon. 

 At the edge of a leaf, it is necessary to cut the flap only at the ends; 

 but when the cocoon is made away from the edge, the flap must be 

 cut along one side also, and frequently the caterpillar cuts along 

 where the edge of the flap is to meet the leaf and pulls up the leaf a 

 little to meet the flap. Fig. 22 well illustrates these variations in 

 cocoon-making. In three or four days, the little caterpillar trans- 

 forms inside its cocoon into the greenish-brown, mummy-like pupa 

 stage (Fig. 21). During the first week in July, many of the spring 

 brood of caterpillars pupated, and in from 12 to 14 days the moths 

 had developed and began to emerge. By means of the spines on its 

 back (Fig. 21), the pupa is enabled to wgrk its way nearly out of one 

 end of its cocoon, and the moth then emerges, leaving the empty 

 pupa skin projecting from the cocoon. 



We reared moths from caterpillars of the spring or June brood on 

 July 16 to 18, but they must have begun to appear earlier, for recently- 

 hatched caterpillars were found in the grapes in vineyards on July 14. 



