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Mayfly - Callibaetis fluctuans

Mayfly - Callibaetis fluctuans
Fairport, Monroe County, New York, USA
September 10, 2007
Size: 10 mm
I'm assuming that this is a mayfly. Can a species be determined?


I don't think this is ferrugineus. That species has many more cross veins in the forewing and the marginal intercalaries are usually double. This specimen seems to match the description of a male C. fluctuans very well.


Moved from Callibaetis.


Your mayfly is a male Callibaetis imago. In New York, (5) Callibaetis species are known, C. ferrugineus ferrugineus, C. fluctuans, C. pallidus, C. pretiosus, and C. skokianus. Yours appears to be C. ferrugineus ferrugineus.

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