This dun is smaller than would normally be expected for Drunella
flavillinea, but it seems to fit the physical description of that species fairly well. I wasn't sure from the dun pictures alone, so I was hoping it would molt into a spinner. It never made it out of the dun's shuck
, but it did begin the process, which allowed me with great care to tease out the last couple abdominal segments of the spinner from the still tightly attached dun shuck
, enabling a more confident ID based on the shape of the spinner's penes
and sub-genital plate. I also collected a nymph of flavilinea
in the same river on the same evening, as well as a shed exuvium that looked large enough to belong to an emerging dun.
The other possibility I considered for a while based on the dun was Drunella pelosa
, which would be the right size, but the other characteristics don't fit.