Mayfly Family Ephemeridae (Hexes and Big Drakes)

fishing in the dark.......
stepping in holes?

I hate the dark........

I don't need the hex........

Len

Sorry no photo
While out fishing I came across a big drake spinner. I think it might be Litobrancha Recurvata. 2 tails 17 mm body length, front pair of legs darker than back two, olive abdomen, darker thorax. Collected August 28th, which is relatively late for Litobrancha. Also could be Hexagenia Rigida or Atrocaudata.

Anyone know if Litobrancha or the Late Hexs are present in Southeast Mn?

I have read in many places that the Hex nymph is a mud dweller. What does this mean? Does this mean they immediately change from egg to nymph and then burrow into the mud until emergence or do they simply burrow in the mud to find food and spend some time in the open water between meals? I have heard comments from fisherman that indicate they know the hatch has been happening when they see small holes in the muddy banks of the river. This is abit confusing to me. Could someone please clarify.

Emergence periods for green drakes usually run for 7-10 days in most streams. However, there are streams in the east where emergence periods are prolonged by some of the nymphs being parasitized by Nanocladius and Epoicocladius midge larvae. In these streams, emergence may be prolonged to 21 days. Unparasitized nymphs emerge before parasitized nymphs, with each group showing separate peaks of emergence about a week apart. This is based upon my own research on green drake emergence in streams with these midge species.

My question here is this: does anybody know of streams that have this type of prolonged emergence (2-3 weeks) in NY, PA, MD, or WV?

Caucci and Nastasi's comments and other comments above are correct. They are really hardy and impressive nymphs when they near maturity. Litobrancha nymphs prefer fine silty, mucky habitats in streams. They can be abundant in mucky side channels to the main stream. Their emergence occurs over a 5-day span, with the large majority emerging within a 3-day period. Therefore, large emergences are rarely encountered. When they do occur, they can be very impressive.

From my experience collecting and rearing these critters, they have a 2-year life cycle in PA and MD. They increase tremendously in size in their second year. Emergence occurred in late May into early June about a week before that of green drakes (Ephemera guttulata).