Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Rat-tailed maggots are the larvae of some species of hoverfly, commonly Eristalis tenax. A characteristic feature of rat-tailed maggots is a tube-like, three segmented, telescoping breathing siphon located at their posterior end. This acts like a snorkel, allowing the larva to breathe air while submerged. The siphon is usually about as long again as the maggot's body (20 mm when mature), but can be extended as long as 150 mm. It is this organ that gives the larva its common name. It lives in stagnant, oxygen-deprived water, with a high organic content. It is fairly tolerant of pollution and can live in sewage lagoons and cesspools.