Subject: march brown or sulphur?
Location: western maryland, usa
May 16, 2014 4:47 am
March Brown or Sulphur? In a debate with a buddy. North Branch Potomac river, May 13, 2014
This debate will most likely take someone with far greater Mayfly identification skills than our own. From our research, the March Brown is a European species, Rhithrogena germanica, and it is not found in North America, so we would eliminate that as an identity of the individual in your images. The images of the March Browns on the First Nature website have patterned wings like the ones in your submitted images, but the pattern appears to be distinctly different. According to Trout Nut, the Sulphur Dun is Ephemerella invaria, and that species, as pictured on BugGuide, does not have patterned wings, so we don’t believe that is the correct identity for this Mayfly either. We tried browsing through the images on BugGuide, and this might be Hexagenia bilineata based on this BugGuide image as well as this Bugguide image. We are looking at the darker border on the hind wings and the shape of the eyes as distinguishing features. There is no common name for Hexagenia bilineata on BugGuide, however the genus is know collectively as the Giant Mayfly, Golden Mayfly or Burrowing Mayfly, according to BugGuide. Since BugGuide readers have different interests than anglers, and we are guessing you and your buddy are anglers, we tried to learn if there is a common name for Hexagenia bilineata among trout fishermen. There is no common name on Trout Nut, but the site does state: “These are huge mayflies. Hexagenia limbata, by far the most important species, is the second largest mayfly in the United States.” Again we cannot confirm that our identification is correct, but we believe you are both incorrect.
Thanks for the info The insect was approximately a #12 (fly fisherman sizing) I think the bilineata is a much larger (#06-08) mayfly than the one I sent. Any other ideas? PJ