syn. Megalodontidae The Megalodontesidae (until recently spelled Megalodontidae) are a small family of sawflies within the Symphyta, containing some 40 species restricted to the temperate regions of Eurasia, and whose larvae feed on herbaceous plants. They are distinguished from the closely-related Pamphiliidae by their serrate or pectinate antennae. Suborder: Symphyta Superfamily: Megalodontoidea