THRIPS. These are minute orange-colored insects found in growing wheat heads, and said to subsist by sucking the juices of the unripe grains, causing them to shrivel. A usual rem edy is to thoroughly dust the field with air-slaked, but dry lime. A species of leaf hopper, Erythro neura, is popularly but erroneously called the grape vine thrip, it sometimes severely injures the foliage of the vine by sucking the juices, causing them to assume a withered and spotted appearance, and sometirnes to shed their leaves. The Entomologist of the Department of Agricul ture, Washington, in one of the late reports says: The Thripicks were placed by Westwood in a separate order called Thysanoptera, or fringed winged insects, from their vvings being ciliated or fringed. Packard places them in the liemiptera. These insects possess two setiform, horny man dibles, which, by their juncture at the tip, form a two-valved syphon. They are of very small size, with bodies long, linear, and depressed; the four narrow wings are fringed with hair, and, wheu at rest, are laid horizontally along the back. By some naturalists they are said to injure wheat, etc. Dr. Packard says they are very injurious to grain and flowers, eating holes in the leaves or corollas, and sucking the sap from the flowers of wheat, in the bottom of which they hide. With a lens we have seen the sap oozing out of small punctures made by these insects on grape leaves. Harris says, they live on leaves and flowers, in buds, or in the crevices of the bark of plants. Their punctures poison plants and often produce deformities in the leaves and blossoms.
Curtis in his work on farm-insects states that the European species, Thrips (Linwthripps) cereal* once destroyed one-third of the wheat-crop in Piedmont, and that the shriveled grains of wheat are caused by the thrips extracting the milky secretion. Westwood says that, the thrips infest wheat to a mischievous extent, causing the grain to shrink. These are only a few extracts from
reliable authorities, to show that by some it is considered an injurious insect, and yet on the other hand Mr. Walsh once said he did not be lieve the true thrips to be a vegetable-feeder, but that on the contrary they are cannibal insects preying upon injurious larvm; and again he says, these insects have hitherto been considered to be vegetable-feeders, but are generally, if not univer sally, iusectivorous, and feed upon the eggs of the wheat-midge (Deplosis tritici) and on gall making larvze. A small yellow thrips is men tioned in Mr. Riley's second report as destroying the eggs of the curculio or plum-weevil. From the above statements it appears that in certain cases the true thrips (not the insect generally known by the name of the grape-tbrips, and which is a leaf-hopper), is in sonae degree benefi cial by destroying other insects: but it appears to be very questionable if advantage from the few insects destroyed by them is at all commen surate with the injuries they inflict on our grain crops, grape vines, fruit trees, and vegetation in general. The remedies suggested f or the destruc tion of these insects, in gardens and greenhouses, are the same as those suggested for plant-lice (Aphides), such as dusting with slaked lime, syringing with whale oil, soap and water ; or strong soap suds, tobacco water, or a decoction. vf aloes or quassia and water and soapsuds, tak ing care not to wet the fruit, when on grape leaves. It must, however, here be again remarked' that the insect, generally known as the grape vine thrips, is a homopterous insect or leaf-hopper, which, when disturbed, leaps with great activity from the leaves, and is not of the same long, linear form as the true thrips, which generally remains stationary upon the leaf, or, at most, crawls slowly over it, and never flies in such swarms as the Erythroneura, or grape-vine leaf hopper, whenever the vines are disturbed.