The life of the microscopic larvae is not completely understood. Within 24 hours after hatching, they are thought to form a protective covering or cyst on vegetation near the water's edge. If the cyst is eaten by a suitable insect, the protective covering dissolves. The released larva bores through the gut wall and into the body cavity of the host. There, it digests and absorbs the surrounding tissue.
Mature worms leave the host to find a mate.
In the spring, these worms can be found in tangled masses. This has led to a variety of stories about their origin. The name horsehair worms refers to the old belief that they came from horse hairs that fell into water. Cabbage hair worm is used in some localities because they can be found in the water droplets that collect in cabbage leaves. According to Greek legend, King Gordius of Phrygia tied a complicated knot.