The sensitive Coffinfly's presence indicates the health of the nearby water source so if you see them, the water must be clean.
At first glance, the Coffinfly appears physically similar to its Mayfly relatives. A long abdomen is tipped with long tail filaments, but the Coffinfly has three "tails" while other species have only two. Coffinflies are further set apart from mayflies by their dark-colored and patterned wings. Like dragonflies, Coffinflies live near slow-moving or still water sources like ponds, creeks, small rivers and shallow lakes. Adults can be found by the hundreds of thousands from the spring to summer if the water source is clean and unpolluted. Coffinflies originally got their name because some species were once found in exhumed coffins.
The Coffinfly undergoes a series of molts (phase changes) as it matures to its adult form. Early larvae look like small versions of lobsters, or crayfish, and they live this early life stage completely under water. They burrow into the sediment or sand at the bottom of the pond or lake, and feed on algae and plant matter. Because they are still developing while living in water, larvae can be indicators of a water system's cleanliness. Even moderate levels of pollution have been known to destroy a local population of larvae.
One intermediate life phase, called the subimago, includes the formation of wings and tiny hairs that start to prevent them from submerging under water. Anglers call this phase a "dun" and may use it - or plastic replications of it - as bait to catch certain species of fish that naturally feed on duns. After another molt, it becomes a more mature adult called an imago, which is also known as a "spinner" to anglers. Fully-developed adults are land-bound and do not feed. Their life span at this stage is very short, leaving only enough time to reproduce before dying. Adults are attracted to lights and may end up clustering on them just before dying, leaving people to find hundreds of dead ones on the ground.
Scientific Name: Ephemera guttulata
Other Name(s): Shad Fly, Green Drake
Size (Adult; Length): 18mm to 23mm (0.70in to 0.90in)
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