GRAPE INSECTS 



411 



Fig. 358. — Fifth 

 stage nymph of the 

 grape leaf-hopper. 



the season advances and more foliage appears, the hoppers 

 work upward on the vines. They hve almost entirely on the 

 under side of the leaves (Fig. 353), from 

 which they suck their food by means of thcnr 

 sharp beaks. They are vcTy active crea- 

 tures, leaping or flying quickly when a leaf or 

 vine is disturbed. 



The adults feed on the vine for two weeks 

 or more before they begin to lay eggs. The 

 female hopper is provided with a slender and 

 sharp ovipositor, by means of which she in- 

 serts the eggs just beneath the lower skin of 

 the leaf. The eggs are semitransparent, 

 slightly bean-shaped, and about three hun- 

 dredths of an inch in length and a third as 

 wide (Fig. 356) . Egg-laying continues for two months or more, 

 and each female may deposit over a hundred eggs. In New 

 York the first eggs are laid about the first of June in normal 



years and towards the middle of 

 the month in ])ackward seasons. 

 The greatest number of eggs are 

 to be found in the leaves in late 

 June. 



In New York the eggs of the 

 overwintering hoppers hatch in 

 9 to 14 days, while in California 

 it requires 17 to 20 days for the 

 same brood and only 8 to 12 

 days for the eggs of the second or 

 spring brood. The length of the 

 egg stage of the second brood has 

 not been determined in the East. 

 The nymphs, which are of a whitish color with red eyes when 

 born, grow slowly and gradually acquire j^ellowish stripes along 



Fig. 359. — Young aphis-lion about 

 to devour a nymph. Enlarged. 



