412 FRUIT INSECTS 



their sides, passing through five stages before acquiring wings 

 (Fig. 357). In New York from 30 to 33 days are required for 

 the development of the nymph, the first-hatched nymphs trans- 

 forming to adults between the first and the middle of July, at 

 which time the maximum number of nymphs in all stages are to 

 be found on the leaves. In unusually long and warm seasons 

 there may be two broods in New York, but as a rule the second 

 brood is only partial. In California there are normally two full 

 broods, which overlap to a considerable extent. The nymphs 



live on the under 

 side of the grape 



^^^K 



\ 



I leaves and suck 

 their food like their 

 parents, the adult 

 hoppers. They 

 first appear on the 

 lower and older foli- 

 age, where the 

 adults begin feed- 

 ing, and later they 

 infest nearly every 

 leaf. The nymphs 



Fig. 3G0. — Grape leaves injured l)y leaf-hoppers Q^ + i^ro. lU + lo 



late ill the season. ^^^ active little 



creatures, scurrying 

 away in all directions when disturbed, and often run to the 

 under side of the leaves or along the leaf-stalks as if to 

 hide. They are good runners, but, unlike the adults, are 

 unable to jump. The effect of the work of the nymphs on 

 the leaves is well shown in Figure 361. The upper sur- 

 face of the green leaf presents a mottled, yellowish appear- 

 ance. Even on badly infested vines, we have never seen the 

 leaves so seriously injured by the nymphs in summer as by the 

 adult hoppers either in the spring or late summer and autumn. 

 Rarely does a leaf turn brown and die from the work of the 



