I caught this female during her egg-laying flight.

I don't know for sure that this is Drunella tuberculata, but that's my best guess for now. It certainly has a different look and much more robust body shape from Drunella lata duns I photographed a couple weeks earlier, so I doubt it's that species. Using distribution records to eliminate other choices narrows this down to Drunella tuberculata or Drunella walkeri. Markings described for the abdominal sternites of the male spinner of Drunella tuberculata are suspiciously similar to those on this female dun. Also, this dun is 9.5mm long (my ruler pic isn't very good, but I'm basing this on measuring the real thing). The size range given in the old Allen & Edmunds keys for walkeri females is 7-8mm, while tuberculata is 9-11mm. For these reasons I'm sticking it in tuberculata for now. This is the only Drunella mayfly I saw all day. I scooped it off the water as it emerged at around 7pm from a big Catskill tailwater.

I was able to identify this female because I captured her while she was mating with an identifiable male.

I positively identified this specimen under a microscope with a good key. It was one of the more common species in a generally light mixed bag of mayflies over a big Catskill tailwater last night. I swooped this one out of the air while it was mating with a female, so I can be certain about her ID as well.

I'm very tentatively (see the connected forum thread) sticking this mayfly in Rhithrogena for now.

Based on the identical size, shape, and relative proportions of different body parts, I'm pretty sure this dun is of the same species as two spinners I collected at about the same time. The color is dramatically different, but that's to be expected with many of these species in the transition from dun to spinner.

For years after I started this website, I was eagerly hoping to find a green drake to add to the collection, but I was never in the right part of the world at the right time. It finally happened on June 1st, 2007.

See the comments for an interesting discussion of the identification of this dun.

I'm confident this dun belongs to septentrionalis, because her legs are just too long for any other Ephemerellid, and her unusual mid-dorsal 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.

I'm just guessing Neoleptophlebia instead of Paraleptophlebia on this one because I tended to find more of their nymphs in the area, but take that with a grain of salt.