Rat-tailed Maggot (Larva of the Drone Fly)
Scientific Name: Eristalis tenax (larval stage)
Order & Family: Order: Diptera (Flies), Family: Syrphidae (Hoverflies)
Size: Body is usually 0.75-1 inch (20-25mm) long; the 'tail' (breathing siphon) can extend significantly longer, sometimes several times the body length.
Natural Habitat
Found in stagnant, oxygen-depleted water rich in organic matter, such as sewage lagoons, manure pits, drains, and dirty ponds.
Diet & Feeding
They feed on decaying organic matter and bacteria suspended in the water, acting as filter feeders.
Behavior Patterns
These larvae use their long, telescoping respiratory siphon (the 'rat tail') to breathe surface air while submerged in foul water. When ready to pupate, they leave the water and seek a drier location.
Risks & Benefits
Generally harmless to humans but can be a nuisance or indicate unsanitary conditions. On very rare occasions, accidental ingestion can cause intestinal myiasis. They are beneficial as decomposers, and the adult drone flies are important pollinators mimicking honey bees.
Identified on: 3/5/2026