_Characteristics._--This pernicious little pest is a bug which multiplies in enormous quantities and sucks the sap out of the vine leaves. Many use the name of thrips to denote this insect, but this is incorrect, as the thrips is an entirely different, much smaller, insect, which so far has never been injurious to the vines of this coast. In size the leaf-hopper is, at maturity, about one-tenth of an inch. In color it is yellowish white, with a few red spots. When the insect approaches maturity, it jumps, but the undeveloped insect or larva only crawls, principally on the underside of the vine leaves, where their cast-off skins can be seen in all stages and sizes. The eggs are laid in the veins of the leaves. The glossy globules which are always seen on leaves where the leaf-hopper is found are not the eggs, as has been supposed by many, but is only the vomit which, when irritated, the hopper throws out either as a defense, or because it desires to rid itself of an unnecessary burden. The leaf-hopper hatches at least two times, or possibly three times, during the summer. Many of the insects remain over during winter time. They feed on almost anything, such as _alfilerilla_ (_Erodium_), etc., but are especially fond of the grapevines, and even in the early spring flock onto the young vine shoots, leaving the less desirable weeds. In some localities this insect is known variously as the white fly, the vine-hopper, or incorrectly as the thrips. _Damages._--The hopper punctures the leaves and causes them to dry up and fall, thus exposing the grapes to the hot sun. The excrement of the hoppers also covers the grapes largely, and spoils their appearance and keeping quality, at least as table grapes. It is principally the table grapes and wine grapes which are injured by this insect; the former are made unfit for shipment, and the latter do not color well when deprived of their leaves. If the grapevines are kept growing, the grapes are less injured, and some growers even contend that the hopper is advantageous, as it causes the leaves to fall and the grapes to mature. _Distribution._--It is not known whether the leaf-hopper is a native of California, and I hardly believe it is. It does not exist in Southern California, but in Northern California and in the San Joaquin valley it is common. In the grape districts of Southern California there is found another variety of leaf-hopper almost twice the size and of a brilliant green color, which only once appeared in such quantity as to do any damage at all. Generally it is quite rare. The _Erythroneura comes_, however, occurs in countless numbers, and often rises in clouds when the vines are approached. In some years it is less common than in others, and after having been plentiful for several years gradually diminishes in quantity, but never disappears entirely.