The name Megaloptera comes from the Greek ‘megalo' meaning large and ‘pteros' meaning wing, an allusion to their large wings. They are commonly known as alderflies, dobsonflies or fishflies, and they measure 10 - 75 mm in length. There are little over 300 described species, in only two families, Corydalidae (dobsonflies and fishflies) and Sialidae (alderflies). Alderflies are found worldwide but dobsonflies are restricted to the Americas and Asia. The order Megaloptera is nearly entirely aquatic. Females lay eggs in masses close to water, often on vegetation, and larvae enter the water after hatching. Larvae are elongated and bear abdominal gills. All larvae are predatory, capturing other aquatic insects, from which they suck their body fluids through a hollow tube of their mandibles. The larval development is slow, taking from one to five years to reach maturity. Mature larvae leave the water and build a chamber under a rock or log, close to water, where they pupate. Adults are short-lived and apparently do not feed. While alderflies are diurnal, dobsonflies are generally nocturnal. Adults display courtship behavior, and fertilization is through a spermatophore.