Insect Order Ephemeroptera (Mayflies)

A thick mating swarm of Tricorythodes mayfly spinners hovers the West Branch of the Delaware near Hale Eddy one early fall morning. View the picture full-size and you'll be able to make out the wings and tails on most of those little white dots.

This was one of many such clouds visible all up and down the river. The mayflies were impressive, but the trout did not hold up their end of the bargain -- there was not a rise in sight.

In this picture: Mayfly Genus Tricorythodes (Tricos).

Some Hexagenia limbata duns and several smaller mayflies litter the surface of this river during a Hex emergence.

In this picture: Mayfly Species Hexagenia limbata (Hex).

A freshly emerged female Drunella cornuta dun.

In this picture: Mayfly Species Drunella cornuta (Large Blue-Winged Olive).

Here's a fresh ball of eggs from a Hendrickson spinner, photographed to show the proper color for the egg-ball on spinner patterns.

In this picture: Mayfly Species Ephemerella subvaria (Hendrickson).

I didn't manage to collect a nymph, but here's the hollow shuck (

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Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.) left over from an emerged dun, showing the basic pattern of the nymph.

In this picture: Mayfly Species Ephemera guttulata (Green Drake).

A huge swarm of Hexagenia limbata spinners gathers over the riffle.

In this picture: Mayfly Species Hexagenia limbata (Hex).

Closeup of some recently emerged Isonychia bicolor nymphs from a small stream.

In this picture: Mayfly Species Isonychia bicolor (Mahogany Dun).

This nighttime flash photograph shows a bunch of Ephoron mayflies flying around during the hatch. So many of them fly around with their dun shucks (

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Here's an underwater view of the pupal shucks of several already-emerged Brachycentrus numerosus caddisflies.

Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.) attached that it seems like they molt from the dun to spinner stage in mid-air. Actually they molt on streamside vegetation like other mayflies, but they sometimes take off to mate before they're completely finished.

In this picture: Mayfly Genus Ephoron (White Flies).