Hendrickson Mayfly Dun - Ephemerella subvaria



Staff member
Dec 13, 2021
Out on Penns Creek yesterday. This mayfly was emerging from about 2:00 - 6:00. Size 12-14. Most import it has three tails!

It was a big honker among all the smaller BWO and caddis coming during the day.

Hendrickson Mayfly Dun - Ephemerella subvaria
Early spring hatch
Start Date: April 19
Time of day: 2:00 - 6:00

Tails: 3
Fore wing: plain
Hind wing: present
Hind wind costal bump: yes
Size: 12mm #12-#14
Brown to tannish body
Wing veins do not diverge at base

Nymph is a crawler type at bottom of streams

Locations found: Northern Pennsylvania, Central Pennsylvania, Western Pennsylvania


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female hendrickson..easy one..
Thanks for the confirmations. I reposted the Subject title as to use for further research down the road. Hope we build this part of the site with good photo's for use as a library.

I have a grannom to post too.

Nice pictures, Dave. I'm still fishing the West Branch, but rarely post anymore. I got blasted a few years ago, and was accused of using indicators. Really bugged me (pun intended). It's great to help beginners with insect identification.
You need to amend your start date. How about March 19?
I just posted a thread about a mayfly I saw with what appeared to be a yellow egg sack. It was the same color and size of the ones in the photos of this post. The may files I saw only had two tails. Do dark Hendricksons have a yellow egg sack? I did not have a camera so I have no photos.
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Here's another Penns Creek female from 4/2/23. It's worth noting that female PC hendos can be yellow, like this one.
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Hendricksons have really become my favorite fly hatch. As long as spring water levels are low there are tons of rising fish to these! Females (light Hendrickson) always tend to be my go to but when they are rejected I'll switch to a male (dark Hendrickson) and usually thats the ticket! I started seeing fishable hatches the first week of April this year in north central PA.
Great pictures here, thanks all.
Penns 3
Getting ready for this years hatch- here is a pic of a male from Penns taken last year.