﻿THE GRAPE LEAFHOPPER IN THE LAKE ERIE VALLEY. 



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Fig. 10.— The grape leafhopper: a and 6, Eggs, par- 

 tially shown under pubescence; c, egg brought 

 into view; d, greatly enlarged egg. All enlarged . 

 (Original.) 



molt, may vary anywhere from 3 to 15. The majority of the nymphs, 



however, complete the stage in from 3 to 5 days. 



Second stage. — In the second nymphal stage the insect becomes 



more active. The eyes lose some of their red color and the body 



assumes a yellowish tint, and at the base of the thorax there appear 



signs of the wing pads in the form 



of lateral buds. The length of 



this stage may vary from 1 to 7 



days. The majority of nymphs 



complete the stage in 3 to 4 days. 

 Third stage. — The insect in the 



third stage moves about very ac- 

 tively when disturbed, running 



with a sidewise motion. Very 



rarely can one be made to hop for 



even the "shortest distance. The 



red has disappeared from the eyes, 



and the yellow markings on the 



thorax have now become quite pronounced. The wing pads extend 



to about the caudal margin of the first abdominal segment. This 



stage may occupy from 1 to 11 days. In most cases from 4 to 6 days 



is required. 



Fourth stage. — In the fourth stage the spines on the segments of the 



thorax and on the legs 

 are more pronounced, 

 and the wing pads now 

 extend to the caudal 

 margin of the second ab- 

 dominal segment. This 

 stage may occupy from 3 

 to 13 days, although the 

 majority of nymphs com- 

 plete it in 3 to 7 days. 



Fifth stage. — In the 

 fifth stage the wing pads 

 are considerably length- 

 ened, extending to about 

 the middle of the fourth 

 abdominal segment. 

 The legs are much longer, 



and the insect runs very rapidly. This stage may cover from 4 to 20 



days. The majority complete it in from 6 to 9 days. 



The total length of time required to complete the nymphal stages, 



from hatching to the last molt, when the mature insect has fully 



developed wings, may vary from 19 to 37 days. 



Fig. 11. — Anal segments of female grape leafhopper and details; 

 a, Anal segments; 6, ovipositor in oviposition; c, sheaths of ovi- 

 positor; d, sting. Greatly enlarged. (Original.) 



