Aphids

Aphids are insects in the order Homoptera, which are also known as plant lice. Some 3,800 species of aphids have been identified worldwide with 1,300 species occurring in North America, which includes some 80 species that are pests of crops and ornamental plants. Aphids have a distinctive pear-shaped body, and most are soft and green in color. The wings are transparent and are held in a tent-like position over the abdomen, which has a short tail, called a cauda. The legs are long and thin, and the antennae are thin and have six segments. Two tube-like structures, called cornicles, project from the fifth or sixth abdominal segments of aphids. The cornicles excrete a defensive chemical when the aphid is threatened.