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BULLETIN 19, U. S. DEPARTMENT OF AGRICULTURE. 



species of wild grapevines did not bear out the supposition that 

 deposition in rows is general in the thin-leaved varieties, for in all 

 other cases where eggs were found on them they were deposited 

 with an apparent disregard for regularity of position. 



Among vineyardists there is commonly a mistaken idea that the 

 small, transparent globules that are seen - on the new growth of the 

 grapevine, especially in the early summer, are the eggs of the grape 

 leafhopper. These are not eggs but are small drops of sap which 

 exude from the rapidly growing leaves and tendrils. 



THE NYMPH. 



The young grape leafhopper, or nymph, when it hatches from the 

 egg, is very minute, white in color, and of the same general form as 



Fig. 9. — Outline of eggs, a and 6, of grape leafhopper on underside of grape leaf with pubescence pushed 

 aside. Greatly enlarged. (Original.) 



the adult, but differing from the mature parent in that it does not 

 possess wings. It attains its growth by casting its skin in a series of 

 five molts. These five nymphal stages are represented in Plate I. 

 The time required for the nymph to reach maturity varies greatly 

 with the different individuals. During the season of 1912 rearings 

 were made of a large number of nymphs. 



First stage. — The newly hatched nymph has a white body and red 

 eyes. It does not run very rapidly at first, but moves over the 

 underside of the leaf with rather an uncertain, "wobbly" gait. The 

 number of days required for this stage, from hatching to the first 



