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a family of herbivorous insects of the order Homoptera. The body measures 0.5–1.5 mm in length. Winged individuals have two pairs of wings that fold rooflike when the insect is at rest. The body of wingless and of some winged individuals is covered with a waxy down. The mouthparts are of the sucking type, with a segmented proboscis. The family embraces approximately 40 species, which are distributed in the temperate zone of the northern hemisphere; the USSR has 20 species.
The Adelgidae live only on coniferous trees. As a result of their stings, spruce trees form galls that resemble small pine cones. The life cycle is often complex; winged and wingless generations alternate, and the insects change host plants. Both winged and wingless females deposit eggs.
Some species of the Adelgidae live on host plants of two species and have a two-year cycle of development. These insects winter on the primary host (spruce) as larvae and in the spring become stem-mothers, whose stings cause gall formation. Migration to the secondary host (fir, larch, or pine) is observed in the second generation. The next year the insects produce a generation of winged females, which return to the primary host and deposit fertilized eggs. Adelgidae that inhabit a single species of tree produce two to four generations annually and reproduce only by parthenogenesis.
Adelgidae damage forest and park conifers. The most harmful species are Adelges viridis, A. abietis, A. laponicus, and A. pinifoliae.
B. R. STRIGANOVA