The Family Sialidae is a group of insects commonly known as Alderflies. These insects have a long-oval shaped body and are typically found near aquatic habitats. There are several synonyms used to refer to this family, including Sialis, Megaloptera, and Corydalidae. Sialis is a genus within the family that includes the common alderfly species found in North America. Megaloptera is a broader term used to describe the order that also includes dobsonflies and fishflies. Lastly, Corydalidae is the alternate family name used for the alderflies, which is derived from the Corydalus genus. Regardless of the terminology used, these insects are fascinating creatures that play an essential role in the ecosystem.