Closeup insects from the Madison River
Male Malenka tina (Tiny Winter Black) Stonefly Adult
View 7 PicturesThis is the smallest stonefly I've ever collected, with a body only 5.5 mm long.
Although not in-focus in my pictures, its first tarsal segment is similar in length to the third, while the second is much shorter. This helps with family-level identification.
Examining this specimen under a microscope shows a membranous lobe on the dorsal (Dorsal: Top.) base of the cerci (Cercus: The left and right "tails" of an insect are known as the cerci or caudal cerci. The middle tail of a three-tailed insect is not.), which is the key characteristic in Merritt & Cummins (4th ed.) to place the genus definitively as Malenka.
Following the species key in Jewett Jr's Stoneflies of the Pacific Northwest, the species appears to be Malenka tina. My dissecting microscope seems to show sternite (Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.) 9 ending in a rounded knob, which distinguishes it from Malenka bifurcata, but the detail is hard to work out.
Also worth noting is that Montana appears to have this species, whereas birfucata is not know there: http://fieldguide.mt.gov/displaySpecies.aspx?family=Nemouridae
Male Cheumatopsyche (Little Sister Sedges) Caddisfly Adult
View 12 PicturesI didn't identify this one directly, but I eventually identified one of several I collected from the same swarms that appeared to be of the same species. (I lost track of which specimen was which in storage.) The microscope pictures come from one of these specimen, not necessarily the same specimen as the DSLR pictures. They key to Cheumatopsyche, and the hind wing venation (Venation: The pattern in which the veins on the wings of an insect are arranged. It is usually one of the most useful identifying characteristics.) that separates them from Hydropsyche is pretty clear in the attached picture as well as another specimen I checked under the scope.
This specimen was one of tens of thousands we saw on a July 1st evening on the Madison, beginning with big swarms around every vehicle and tree at the Eight Mile Ford access point and continuing all up and down the river bank. We somehow didn't catch any trout, perhaps because they were stuffed with pupae from when these things emerged. Or maybe we just weren't fishing well. Either way, this one represents a major hatch there.
I somehow forgot to photograph this important specimen against the hooks size chart, but fortunately I preserved a few. The body length is about 6 mm, and total length from head to wingtip is 9 mm.
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