WHIRLIGIG BEETLE

any member of the approximately 700 species of the cosmopolitan insect family Gyrinidae (order Coleoptera). These beetles are usually seen in groups, spinning and whirling around on the surfaces of quiet ponds or lakes. Whirligig beetles prey on insects and other creatures that fall on the water surface. Their bodies are oval, flattened, and metallic bluish black in colour. The front legs are long and slim; the middle and hind pairs are short and flattened. They have well-developed wings and dive and swim underwater when attacked. The two pairs of compound eyes, one above and one below the water surface, provide simultaneous vision in both environments. The female whirligig beetle deposits cylindrical eggs in parallel rows on underwater vegetation. The long, narrow larvae have only three pairs of true legs; the fringed gills on each abdominal segment, however, make them resemble centipedes. Hooks at the end of the abdomen anchor the larva when it captures food. At the pupal stage the larva emerges from the water, hangs upside down on shore vegetation by its hooks, and forms a pupal case from dirt and saliva. When disturbed, whirligig beetles exude a disagreeable-smelling milky liquid, which probably serves for protection; the fluid of Dineutes americanus smells like apples.