LAC-INSECT. Any one of the several scale insects of the coccid genus Carteria, which secretes lac (q.v.). Carteria lacra, of Asia. secretes the gum lac or stick lac of commerce and is found upon fig-trees (Rhannus, Croton and Buten). Carteria larrecr, of the Southwestern United States and Mexico, feeds on the creosote-bush (Larrea Mexicana) and secretes quantities of lac. which, however, has not been commercially used. A third species (Carteria Mexicana) oc curs in Mexico upon the mimosa, but its product has not been used in commerce. The body of the adult female is sac-like in form, with no legs, and is imbedded in a mass of lac. The anal end of the body is furnished with three promi nent tubercles, of which one. the largest. is really the torminal seginent of the body, each of the others hearing a perforated plate which is presumably the organ through which the lac is excreted. If a bit of eounnercial stick lac be examined, it will be found to consist of an incrustation. one-fourth to three-eighths of an inch in thickness, upon small twigs. This in crustation is filled with elongated cells in each of which is the shriveled remains of the insect which originally filled the cell and determined its size and shape. The insect. is of the shape of a
jug with three necks. and each of the necks fits into a tubular opening from the cell and really forms a lac-tube, each being provided with a spiracle for breathing purposes. The females are viviparous, and the young, reddish in color and provided with functional legs, issue from one of the tubes, out upon the twig and settle. The males, as with other scale-insects, beeome winged. The lac produced by Carteria larrefr upon the creosote-bush is chemically identical with the commercial Asiatic product. hut the masses produced by the individual insects are not crowded together as compactly, and pre serve a rather globular form. Consult: Stillman, of the Lac," in The American Naturalist, vol. Niv. (Philadelphia, 1Ss0 ) Comstock, Annual Report of the United Ntatcs Department of Agri culture for 1881-62 (Washington, 13S2) ; O'Con nor, Lae: Production. 31anufacturc, and Trade (Calcutta, 2d ed., 1876).