Looking to do something outdoors and asocial during July 4th of the year of Covid-19, I took my wife to a small stream full of feisty westslope cutthroat trout. Of course, being July 4th, there were a few people around the easy-to-access spots (i.e. places to drive and set up a cushy camp ten feet from the truck), but it was easy to walk past them and have a beautiful little stream to ourselves. I'm both baffled and grateful that so few people see the value in chasing little trout in pretty little streams.
It's remarkable what thick hatches, and especially spinner flights, can come from a species few anglers have ever heard of. The genus Cinygmula is thought to produce unremarkable spinner flights, but this one would certainly have gotten the trout going if it weren't happening just before dark on a small stream where there isn't a lot of nocturnal feeding.
Male Rhithrogena hageni (Western Black Quill) Mayfly SpinnerView 15 PicturesI collected this spinner from the trail (old logging road) above a whitewater canyon on a small stream in the Cascades. I'm fairly positive on the ID: in Traver 1935 it keys out to Rhithrogena doddsi, which is now a synonym (Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.) of Rhithrogena hageni. The penes (Penes: The paired genital structures of most male insects, which vary widely in form and are one of the main characteristics used for species identification.) differ slightly from the drawing in that book, but they're a very close match to drawing from the original hageni description in Eaton 1885.
Lastly, I have included here a couple pictures of the genitalia of a different specimen collected on the same evening, from the same river, and I think even the same swarm (although I don't recall that 100 %). They're angled a bit differently, and I couldn't locate the mid-ventral (Ventral: Toward or on the bottom.) spines, but I'm guessing I'm just seeing intra-species variation.
Female Rhithrogena hageni (Western Black Quill) Mayfly DunView 7 PicturesI was surprised by the olive cast on the body of this female Rhithrogena dun, which led me to mistake it for a western green drake (Drunella) in the field. I was pleasantly surprised to get a closer look and find something I hadn't collected yet. Its species ID is based on proximity to male spinner collected on the same trip, as well as physical similarity (size, tergite (
One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.
Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) coloration, dark streaks on the femora (
The femur of this Isonychia bicolor mayfly spinner is highlighted in red.
Femur: The main segment of an insect's leg close to the body, in between the tibia and the trochanter.)) to that specimen.