hatch and the first instar larvae either fall directly into the stream or if not, immediately search for water. There the larvae live for up to five years, going through 10-12 instar molts. When they have finally reached maturity, the larvae leave the water and find a rock, log, or anthropogenic debris, typically close to the stream but sometimes up to 40 m away. There they construct a chamber for pupation and spend several days to several weeks as prepupae before shedding the exoskeleton and spending about a week to two weeks as pupae. The pupae are yellow-orange with dark spots on the dorsum of the abdomen, covered in minute setae, and exarate (i.e. the developing appendages and mouthparts are attached only at their proximal ends). Although the males have a small tubercle on the prothoracic sternum and a slightly wider head than the females, the mandibles are not as noticeably divergent as in the adults. Finally, the pupae emerge from the chamber, leaving behind the larval and pupal skins. Uses Hellgrammites are popular among anglers as bait due to their large size, endurance, and ferocious temperament. John Henry Comstock suggested securing a net or wire screen to the rocky bottom of a creek and disturbing the rocks just upstream of the screen as a method to catch the larvae. They often run for relatively high prices at bait shops, leading to over-exploitation in some areas and regulation of sale in certain states. Some anglers instead use lures in the shape of hellgrammites. Although not to the same extent as the larvae of mayflies and caddisflies, hellgrammites are intolerant of polluted waters and may have potential to be used as indicators of water quality. As the adults are strongly attracted to lights, entomologists and collectors often use black light and mercury-vapor light traps to capture them. Gallery References Further reading Glorioso, M. (1981). "Systematics of the dobsonfly subfamily Corydalinae (Megaloptera: Corydalidae)". Systematic Entomology 6(3) 253–90. . External links Dobsonfly. Aquatic Critters. Missouri Botanical Garden. Genus Corydalus. Tree of Life Web Project. 1997. Eastern dobsonfly, Corydalus cornutus. Featured Creatures. UF/IFAS Aquatic insects Corydalidae