Dobsonflies, (larvae are also known as hellgrammites) are insects in the order Megaloptera. They have impressive sexual dimorphism; males have a extremely elongated mandibles, whereas the females do not. I have seen lots of misinformation over the years about these insects. Though they do have a strange appearance (apparently terrifying to some) theyre not harmful whatsoever. In fact, theyre very beneficial predators in aquatic ecosystems. They are what we call an indicator species, meaning that