Rusty Spinners

This is one of the most prolific genera of mayflies in North American trout streams. Their small size permits the growth of up to three generations per year, and they are good dry-fly insects because they often hatch in impressive numbers and the duns ride the water for a long time before taking flight.

Baetis is probably the most misidentified genus in the angler's mayfly world. Many fly anglers see anything too small to imitate with a size 16 Adams and call it Baetis. In reality, Baetis is the most prominent of several very similar abundant genera in the family Baetidae. It seems every species in the family is perpetually being reclassified, and identifying any of them, even to genus level, is difficult.

The angler who wants to be accurate has two choices. Most people call these flies "Blue-Winged Olives," a name which has lost all meaning because people apply it to several dozen species which mostly have neither blue wings nor olive bodies. It's better to just call them "little (whatever color they are) mayflies." The other good choice is to call them "Baetids," the general Latin name for members of the Baetidae family, unless you've had them scrutinized under a microscope. Most of the specimens on this site can't be keyed below the family level from the pictures. So the next time a fishing buddy identifies a little greenish mayfly from a distance as Baetis vagans, just smile and nod...

This is one of the most challenging mayfly hatches on waters across the country.

Ephemerella dorothea consists of two distinct subspecies (Subspecies: Entomologists sometimes further divide a species into distinct groups called subspecies, which have two lower-case words on the end of their scientific name instead of one. The latter is the sub-species name. For example, Maccaffertium mexicanum mexicanum and Maccaffertium mexicanum integrum are two different subspecies of Maccaffertium mexicanum.) which both produce excellent action. Ephemerella dorothea dorothea is a small species of Sulphur in the East, and Ephemerella dorothea infrequens (formerly Ephemerella infrequens) is one of the two main Pale Morning Dun hatches of the West.