﻿THE GRAPE LEAFHOPPER IN THE LAKE ERIE VALLEY. 



13 



newly transformed adult these yellow markings are hardly discerni- 

 ble (fig. 8), the whole body being very light straw color. In a short 

 time, however, they become more pronounced. Along toward the 

 middle of August the salmon color begins to appear, first as a light 

 tint on the thorax and at the base of the elytra and in a short time 

 extending to the tips of the wings. As the season advances the 

 salmon color deepens until the insect takes on the more pronounced 

 red markings of the wintering adult. 



THE EGG. 



The eggs of the grape leafhopper are not more than three-fourths 

 of a millimeter long and are slightly curved (see fig. 10, d)„ . They 

 are semitransparent, with a yellowish tinge, and are very difficult 

 to locate, since they are deposited beneath the 

 epidermis of the underside of the grape leaf, which 

 in most varieties is covered with a heavy pubes- 

 cence. It, is very difficult to detect them with 

 the naked eye even after the most careful search. 

 They may be located, however, with the aid of a 

 hand lens or dissecting microscope by examining 

 the underside of the leaf in bright sunlight. 

 Under these conditions the eggs appear as slight 

 shiny elevations under the epidermis. By care- 

 fully scraping away the pubescence covering this 

 area the outline of the egg maybe more plainly 

 discerned. Figure 9 is an enlarged photograph 

 showing the outlines of two eggs beneath the epi- 

 dermis of a leaf of Concord grape. The eggs are 

 extremely delicate and are very easily crushed 

 when an attempt is made to remove the thin, 

 semitransparent layer of leaf skin or epidermis 

 underneath which they have been tucked by means of the slender 

 ovipositor of the female (fig. 11). Figure 12 shows the anal segment 

 of a male of the same species, with its genital armature. 



The eggs are usually deposited singly over the surface of the leaf, 

 sometimes in or near the ribs and veins, but usually in the spaces 

 between them. They do not appear to be placed in any regular 

 order, but occasionally several may be found in close proximity. 

 In one instance, in the leaf of a Clinton vine, three eggs were found 

 quite close together with the long axis of all extending in the same 

 general direction. Slingerland mentions finding the eggs laid from 

 six to nine in a row in leaves of the Clinton grape. In this variety 

 the leaf is less fleshy and has less pubescence than have the leaves 

 of nearly all of the other varieties of grapes grown in the East. 

 Examinations of the location and proximity of eggs in thin-leaved 



Fig. 8. — Adult grape leaf- 

 hopper, summer form, 

 showing the lighter shade 

 of color markings of the 

 elytra. Greatly enlarged. 

 (Original.) 



