**Description:** The aquatic larvae of Mayflies, featuring soft bodies and three distinct, thread-like tails (cerci).
**Size:** 0.2 to 1 inch long.
**Identification:** Look for the three tails and a row of gills along the sides of the abdomen. They move with a distinct swimming or crawling motion.
**Behavior:** Highly sensitive to water pollution and low oxygen. Their presence is a gold standard for assessing watershed health.
**Habitat:** Under rocks in clean, well-oxygenated forest streams; primary food for Brook Trout.