Updates from May 12, 2007

This is surely the most distinctive-looking species in Ephemerellidae. I like the rugged, spindly look. If mayflies made movies, Penelomax septentrionalis would probably play the supervillain. Maybe I should take a break and get something to eat.

I captured this specimen in the same color as this photograph, during its egg-laying flight. The emergers are much lighter.

Several users have interesting comments in the discussion of this specimen, but this observation by Creno is especially good: Also, this is what I would call an "immature" pupa. The wingpads of caddis pupae darken to nearly black as the enclosed adults near emerging. The darkening is the developing adult wing inside the pupal wing pad. The ultimate coloration of the adult wing is not very apparent in most pupal wing pads as the majority of the adult wing coloration comes from the color/position of the adult wing hairs and setae. But dark pupal wingpads are a good indication that the emergence will occur very soon, likely that day or so, and that the adult parts are sufficiently developed within the pupae to make a species determination from the specimen, particularly if it is a male.

This yellow drake dun hatched out of my aquarium over a month before her brethren in the wild are slated to emerge. She seems a bit small, and that might be the reason.

I photographed this nymph in the middle of molting between one instar and the next (not hatching).