BULLETIN 108. 



THE GRAPE LEAF-HOPPER. 



187 



account of the egg and the first published pictures were given by 

 Slingerland 1 in 1901. 



It is now very well known that the eggs of this insect are laid just 

 beneath the epidermis on the underside of the grape leaf. This is by 

 far the most usual position, though they were occasionally found on 

 the upper surface. They are generally distributed over the leaf surface, 

 and occupy no special position in relation to the veins or ribs of the 

 leaf. Some will be found in the tissue of the rib itself, a good many 

 along the side of the ribs, and others scattered about over the general 

 surface. They will be found also around the very edge of the leaf. 

 In thousands of eggs seen during the summer 

 we failed to find any arranged in rows as was 

 found by Slingerland in New York.- The six 

 or seven eggs laid in a row parallel with one 

 another would represent a single laying of a 

 hopper, and there is no reason why this should 

 not be done occasionally, but it is not the 

 usual occurrence here. We have found them 

 with two or sometimes three arranged more 

 or less parallel, but never more than this num- 

 ber. In our individual breeding cages, where 

 we obtained several hundred eggs, and where 

 the space was limited, they were promis- 

 cuously scattered about, one in a place. 



We confined several hoppers, taken in pairs, 

 and liberated these in cages on currant, black- 

 berry, loganberry and almond, peach, cherry, 

 and a few other plants, but did not succeed 

 in obtaining eggs from these food plants. In 

 most cases the insects were found dead when the cages were examined 

 three or four weeks later. We selected the particular plants named 

 because they were convenient, and not because the eggs would be more 

 likely to be laid on these than on other plants. Possibly more nearly 

 related plants, botanically, would be found suitable for oviposition. 

 The Virginia creeper is said to be readily attacked by this insect, 3 and 

 we presume eggs are laid on this plant. Since, however, this species is 

 a grape pest exclusively, that is, during the growing season, and all the 

 experience indicates that it feeds only upon the grapevine, it may be 

 stated, so far as the economics of the insect is concerned, that the eggs 

 . are laid only in the leaves of the grape. 



1 Cornell Agr. Exp. Sta. Bull. 215. 



2 Slingerland. Bull. 215, Cornell Exp. Sta. 



3 Gillette, Colo. Sta. Kept. 1000. 



Fig. 9. The eg dis- 

 sected from the leaf 

 and photographed on 

 a microscope slide. 

 Particles of leaf tissue 

 are shown still ad- 

 hering to the egg. 

 Greatly enlarged. 



