Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York

Blue-winged Olives
Baetis

Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.

We were lucky to be able to fish through this storm as it skirted around us to the north, giving us just enough clouds to prompt a BWO hatch but keeping the lighting at a safe distance.

From Slough Creek in Wyoming

Stream photos

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Holocentropus Caddisfly Larva Holocentropus Caddisfly Larva

Dorsal view of a Holocentropus (Polycentropodidae) Caddisfly Larva from the Yakima River in Washington

This one seems to tentatively key to Holocentropus, although I can't make out the anal spines in Couplet 7 of the Key to Genera of Polycentropodidae Larvae nor the dark bands in Couplet 4 of the Key to Genera of Polycentropodidae Larvae, making me wonder if I went wrong somewhere in keying it out. I don't see where that could have happened, though. It might also be that it's a very immature larva and doesn't possess all the identifying characteristics in the key yet. If Holocentropus is correct, then Holocentropus flavus and Holocentropus interruptus are the two likely possibilities based on range, but I was not able to find a description of their larvae.

11 Recently Added Photos

27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.

Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Specific collection sites for Capniidae

The specific collection location data from this map were pulled from the Global Biodiversity Information Facility (GBIF) website under the Creative Commons license. Data there come from a variety of sources, some of which are populated by hobbyists. Both the precision of the location and accuracy of the identification could be low. This map is not an authoritative scientific source, nor an exhaustive list of everwhere this taxon is found, but it should be good enough for anglers. Click each marker on the map for more information about that report, including a link to more details on GBIF.

There are 8898 reported locations for this taxon in the database. Only randomly selected 2000 have been shown here to avoid overloading your browser. Reloading the page will again choose a random 2000.

Blue-winged OlivesBaetis

Specific collection sites for Capniidae

Specific collection sites for Capniidae

Blue-winged Olives
Baetis