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Dark Cahills



Like most common names, "Dark Cahill" can refer to more than one taxon. They're previewed below, along with 8 specimens. For more detail click through to the scientific names.

Mayfly Species Maccaffertium ithaca

These are sometimes called Dark Cahills.
Maccaffertium ithaca (Light Cahill) Mayfly NymphMaccaffertium ithaca (Light Cahill) Mayfly Nymph View 9 PicturesThis specimen seems to be of the same species as a dun I photographed which emerged from another nymph in the same sample.
Collected May 29, 2007 from in
Added to Troutnut.com by on June 4, 2007
Female Maccaffertium ithaca (Light Cahill) Mayfly DunFemale Maccaffertium ithaca (Light Cahill) Mayfly Dun View 10 PicturesThis female looks very much like a male I collected a few hundred miles away a few days later, so I'm guessing it's the same species, which I believe is Maccaffertium mediopunctatum.
Collected May 23, 2007 from in
Added to Troutnut.com by on June 4, 2007

Mayfly Species Maccaffertium vicarium

These are sometimes called Dark Cahills.
In the East and Midwest this is one of the most important hatches of the Spring. They are large flies which emerge sporadically, making for long days of good fishing.

This species contains the two classic Eastern hatches formerly known as Stenonema vicarium and Stenonema fuscum, the "March Brown" and "Gray Fox." Entomologists have discovered that these mayflies belong to the same species, but they still display differences in appearance which the trout notice easily. Anglers should be prepared to imitate both types.
Maccaffertium vicarium (March Brown) Mayfly NymphMaccaffertium vicarium (March Brown) Mayfly Nymph View 5 Pictures
Collected April 19, 2006 from in
Added to Troutnut.com by on April 21, 2006
Male Maccaffertium vicarium (March Brown) Mayfly DunMale Maccaffertium vicarium (March Brown) Mayfly Dun View 10 PicturesI collected this mayfly on the same trip as a female of the same species. After these photos it molted into a spinner. This is the form of Maccaffertium vicarium which anglers call the "Gray Fox."
Collected May 28, 2005 from in
Added to Troutnut.com by on May 24, 2006
Female Maccaffertium vicarium (March Brown) Mayfly SpinnerFemale Maccaffertium vicarium (March Brown) Mayfly Spinner View 7 PicturesI collected this mayfly on the same trip as a male of the same species. They are Maccaffertium vicarium mayflies of the type formerly known as Stenonema fuscom, the "Gray Fox."
Collected May 28, 2005 from in
Added to Troutnut.com by on May 24, 2006

Mayfly Species Cinygmula reticulata

These are very rarely called Dark Cahills.
Cinygmula reticulata is probably the second most important species of Cinygmula behind Cinygmula ramaleyi, perhaps because the waters where it can be found in good numbers are often more remote. They have been reported as abundant in many high country streams of the Southern Rockies as well as the High Sierra's Eastern slope. An obvious difference in their coloration may be the easiest way to tell them apart. Cinygmula ramaleyi is more somber with a brownish body and dark gray wings and is often confused with the similar sized and colored Ephemerella tibialis, in spite of the difference in tail counts. Cinygmula reticulata on the other hand is a bright cinnamon dorsally with pale creamy legs and pale wings that are often a brilliant canary yellow. This is one of North America's most beautiful mayflies.
Cinygmula reticulata (Western Ginger Quill) Mayfly NymphCinygmula reticulata (Western Ginger Quill) Mayfly Nymph View 1 PicturesI collected several live specimens of nymphs and reared them to the imago (Imago: The sexually mature adult stage of the mayfly is called the imago by scientists and the spinner by anglers.) stage. They were C. reticulata. The interesting thing is they were collected in May and were emerging along with Rhithrogena (March Brown). This seems to be an overlooked hatch since in some rivers it emerges very early, before runoff.
Collected May 10, 2009 from in
Added to Troutnut.com by on June 26, 2011
Female Cinygmula reticulata (Western Ginger Quill) Mayfly DunFemale Cinygmula reticulata (Western Ginger Quill) Mayfly Dun View 1 Pictures
Collected June 15, 2011 from in
Added to Troutnut.com by on June 24, 2011
Male Cinygmula reticulata (Western Ginger Quill) Mayfly SpinnerMale Cinygmula reticulata (Western Ginger Quill) Mayfly Spinner View 7 PicturesThe 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 “cross veins in costal half of fore wing only, slightly margined with brown” and “wings tinged withamber at base and along costal margin of both wings” (gartrelli) as opposed to “all cross veins 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 (Ventral: Toward or on the bottom.) median marks are supposed to be “traces” for reticulata and “present” for gartrelli. Descriptions for both species involve semi-hyaline (Hyaline: Highly transparent, or glassy; usually refers to insect wings, especially those of mayfly spinners.) anterior (Anterior: Toward the front of an organism's body. The phrase "anterior to" means "in front of.") abdominal segments not present on my specimens. Distribution records suggest reticulate lives nearby, so I'm going with that, but I can't confidently rule out gartrelli.
Collected August 1, 2020 from in
Added to Troutnut.com by on August 18, 2020
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