This fascinating mayfly is among the most distinctive in the Ephemerellidae family, because it has unusually long legs in both the nymphal and adult stages. The nymphs have a strikingly rugged, spindly appearance, and the adults are a strikingly deeper, amber-yellow color than other Ephemerellidae duns.
» Species septentrionalis
This species was overlooked in the fly-fishing literature for many years. The first details appear in Fly-Fishing Pressured Water, which states that this species (formerly called Ephemerella septentrionalis) sometimes supports hatches of Ephemerella invaria. Ernest Schwiebert's Nymphs Volume I: The Mayflies: The Major Species seconds that claim, suggesting that it generates fishable hatches which may go unnoticed due to confusion with both Ephemerella invaria and Ephemerella dorothea. However, the long legs, thin dorsal (Dorsal: Top.) stripe, and more vivid color make it easy to tell them apart upon close inspection. Where & When
Region:There are records of this species from Tennessee north into Ontario and Quebec. They begin in early May near the southern end of their range, and continue into midsummer in Canada. Expect them from mid-May through early June in the popular fly fishing waters of Pennsylvania and New York, from the limestone spring creeks to the freestone Catskill and Poconos waters. Their timing coincides with the more common and similar Ephemerella invaria.Hatching BehaviorTime Of Day (?): Late afternoon early in the season; twilight later on
EastTime Of Year (?):
May through midsummer
Spinner BehaviorTime Of Day: Twilight
Substrate: Weedy stretches of streamThese nymphs may be most abundant in very small streams, but they are known from larger rivers as well, and I have collected them from the main stem of the Delaware.
Pictures of 3 Mayfly Specimens in the Species Penelomax septentrionalis:
Female Penelomax septentrionalis Mayfly Dun
View 10 PicturesI'm confident this dun belongs to septentrionalis, because her legs are just too long for any other Ephemerellid, and her unusual mid-dorsal (Dorsal: Top.) stripe matches those of two easily identified nymphs I collected some miles downstream.
This really pretty mayfly was in kind of bad shape when I found it crippled on the surface, and bouncing around in my container with a bunch of green drakes didn't help.
Recent Discussions of Penelomax septentrionalis
Anyone know more about Ephemerella septentrionalis? 11 Replies »
I found about one sentence on these in Gonzo's book, and haven't seen them mentioned anywhere else in fly fishing literature. Nor is any of the scientific literature I have on them particularly interesting (just descriptions). Now that I've collected a few and see what unique-looking nymphs they've got, I'm really curious about them.Reply
Your Thoughts On Penelomax septentrionalis:
You must log in
at the top of the page to post. If you haven't registered yet, it's this easy: