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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.

Male Cinygmula reticulata (Western Ginger Quill) Mayfly Spinner Pictures

The lengths of the wing and body, measured with a caliper, are both 8 mm.

Keys in Needham's 1935 Biology of Mayflies point to either Cinygmula reticulata or Cinygmula gartrelli. It seems to have crossveins in costal half of forewing only, slightly margined with brown and wings tinged with amber at base and along costal margin of both wing (gartrelli) as opposed to all crossveins of both wings faintly but broadly margined with pale smoky and wings entirely amber-tinged (although there is a slight amber tinge throughout, just more pronounced in places) as in reticulata. However, wing length reported for reticulata (9 mm) is closer to this specimen than gartrelli (10 mm). Ventral median marks are supposed to be "traces" for reticulata and "present" for gartrelli. Descriptions for both species involve semi-hyaline anterior abdominal segments not present on my specimens. Distribution records suggest reticulata lives nearby, so I'm going with that, but I can't confidently rule out gartrelli.

This mayfly was collected from Mystery Creek #237 in Montana on August 1st, 2020 and added to Troutnut.com by Troutnut on August 18th, 2020.

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