DOBSONFLY

any insect of the family Corydalidae (order Megaloptera) with four net-veined wings. Dobsonflies are found in North and South America, Asia, Australia, and Africa. Corydalus cornutus is a large insect with a wingspread of about 13 cm (5 inches). The jaws (or mandibles), considerably larger in the male than in the female, are characteristic of the insect's sexual dimorphism and may exceed 2.5 cm. Females lay up to about 3,000 eggs in whitish clusters near streams; after the eggs hatch, the young larvae crawl to the water and mature there in two or three years. The maturing larvae, large (sometimes 8 cm long) and blackish in colour, live beneath stones in rapidly flowing streams. These larvae have strong biting mouthparts and are ferocious predators on other aquatic insects and small invertebrates. They can also inflict painful bites on humans. Mature larvae migrate from their freshwater habitat to wet soil, moss, or decaying vegetation near the water to form pupal cells from which adults emerge. The larvae, sometimes known as hellgrammites, or toebiters, are eaten by fish, especially bass, and are used as bait by fishermen. Megaloptera larvae also act as important environmental indicators due to their high intolerance of water pollution.