Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
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Stonefly Genus Malenka (Tiny Winter Blacks)
Genus Range
Specimens of the Stonefly Genus Malenka
1 Male Adult
This 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 base of the cerci, 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 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
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 base of the cerci, 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 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
Start a Discussion of Malenka
Stonefly Genus Malenka (Tiny Winter Blacks)
Taxonomy
Species in Malenka
Malenka tinaTiny Forestflies
1
7
Species in Malenka: Malenka tina
10 species (Malenka bifurcata, Malenka biloba, Malenka californica, Malenka coloradensis, Malenka cornuta, Malenka depressa, Malenka flexura, Malenka marionae, Malenka perplexa, and Malenka wenatchee) aren't included.