From Canada to the Gulf and from the Atlantic to the Pacific, wherever the grape is grown, the small leaf-hopper (_Typhlocyba comes_) infests the grape in greater or less numbers, feeding on the lower surface of the leaf. Grape-growers commonly call these insects "thrips," a name, however, which really belongs to a very different class of insects. The injury done by this pest varies greatly with the season and the locality, in some regions it being comparatively harmless and in others exceedingly destructive in seasons when it occurs in abundance. There is great variation also in individual vineyards, those near favorable hibernating places and early spring food plants often being injured seriously season after season in succession. These leaf-hoppers obtain their food by piercing the epidermis on the under side of the leaf surface and sucking the sap, and add further injury by inserting their eggs underneath the skin of the leaf. The punctures greatly decrease the starch-producing area of the leaf with the result that the vigor of the plant is lowered, and the quality of the fruit decreased. [Illustration: FIG. 41. First four stages of the grape leaf-hopper. (Enlarged.)] [Illustration: FIG. 42. The fifth and the mature stages of the grape leaf-hopper. (Enlarged.)] The life history of the leaf-hopper is very well known. The eggs are deposited in June or early July, and hatch from June 15 to July 10 in New York, the season being earlier or later as one goes south or north. The young leaf-hoppers are wingless, the nymph stage, but reach the adult stage in late July and August, at which time many of them mate, and eggs are laid from which a second brood may develop, although usually only one full brood is produced in a season in the northern states. Figures 41 and 42 show the several life stages of the leaf-hopper. Insects which become adults in the latter part of July feed on the foliage until autumn and then seek winter quarters, passing the winter in the adult stage under fallen leaves, in dead grass or other similar protection. The hibernating place must be dry and for this reason sandy knolls are most favored by the insects. The adults emerge in the warm days of spring and then seek food first on the strawberry, then migrate to red and black raspberries or blackberries, if raspberries are not present. They remain upon these hosts until the grape leaves expand and then migrate to these to feed, lay their eggs and die.