I noted in my last entry that I should stick to the small mountain streams for awhile: should have done that today. The Doyles River at Blufton Road was high -- and actually a little off color. Consequently, a lot of the insects I found were covered with silt, though it is true, Drunella nymphs are often that way when I find them. Must be where they live.
The spiny crawler in the photo above is Drunella cornutella. It's one of three species we have in our streams -- the other two, D. walkeri and D. tuberculata -- but it's the one we most commonly see in late May and June. I netted four of them today in the short time that I worked in the stream, two of them already mature -- black wingpads.
Drunellas are easy to spot, those muscular fore femora give them away. For D. cornutella, let me turn to Steve Beaty's "The Ephemeroptera of North Carolina." "D. cornutella -- nymphs 6.4-8.5 mm; head smooth with moderately long lateral frontoclypeal projections but less than half as long as the distance between them; median ocellar tubercle blunt to moderately sharp; femora with dense row of long, fine setae on posterior margin; ratio of mesotibia to mesofemur <0.85; abdomen without paired dorsal tubercles. Collected in spring through early summer. Common."
The nymphs that I found were 7-7.5 mm. We can see the critical features for the cornutella ID in a single microscope picture. Also clear in that photo, the tubercles on the front edge of the forefemora that signal the genus ID.
Back to the small streams tomorrow.