GRAPE INSECTS 



405 



the scales surrounding the buds, under the loose bark on the 

 canes (Fig. 348), and more rarely in small clusters on the upper 

 or under surface of the leaves. Oviposition may continue for 

 over forty days and each female may 

 deposit from twenty to over one hun- 

 dred eggs. The time required for the 

 eggs to hatch depends largely on the 

 temperature; eggs laid in April while 

 the weather is cool do not hatch very 

 much before those laid in June. The 

 egg stage may last from twenty to 

 sixty days. 



When newly hatched the grubs are 

 scarcely a sixteenth of an inch long and 

 of a very dark brown color, almost as 

 dark as the blackish spots on the body. 

 They soon make their way to the young 

 leaves, where they begin to eat little 

 irregular holes through the skin and 

 into the soft inner tissues. They feed 

 almost entirely on the upper surface, 

 several grubs usually working on the 

 same leaf (Fig. 351). Sometimes the 

 grubs are numerous enough to riddle 

 the foliage quite badly, but the actual 

 injury to the vine from their work is 

 never serious. The larvae become full- 

 grown in between two or three weeks 

 and are then about one third inch in 

 length, dark yellowish brown in color 

 and marked with regular rows of blackish spots ; the head, legs, 

 and thoracic and anal shields are black (Fig. 349). In New 

 York the grubs are found on the leaves during June and the 

 first half of July. 



Fig. 350. — Grubs erf 

 the grape-vine flea-beetle 

 feeding on a blossom 

 duster. 



