Adams

Mayflies

Caddisflies

Stoneflies

Scientific Names

Match	Scientific Name
	Siphlonurus alternatus
	Siphlonurus quebecensis
	Siphlonurus rapidus

Like most common names, "Adams" can refer to more than one taxon. They're previewed below, along with 5 specimens. For more detail click through to the scientific names.

Mayfly Species Siphlonurus alternatus

These are often called Adams.

This species occasionally produces important spinner falls. Its spinners may join the swarms of Siphlonurus quebecensis or Siphlonurus rapidus, amplifying the importance of all three species.

Siphlonurus alternatus (Gray Drake) Mayfly Nymph

View 2 Pictures

Collected June 8, 2005 from in
Added to Troutnut.com by on May 26, 2006

Female Siphlonurus alternatus (Gray Drake) Mayfly Spinner

View 7 PicturesI'm tentatively classifying this one as Siphlonurus alternatus, because it seems to fit that species best in the old keys in Needham's Biology of Mayflies, but I'm hesitant because I can't find documentation that southwest Montana or the surrounding area is within the species' range, although they are widely distributed throughout eastern North American and western Canada.

Collected July 2, 2019 from in
Added to Troutnut.com by on July 18, 2019

Mayfly Species Siphlonurus quebecensis

These are often called Adams.

This is the Siphlonurus species I have encountered most frequently on Eastern trout waters. I often find its spinners swarming in a mix with Siphlonurus alternatus, and I have read that Siphlonurus rapidus may join these groups as well.

Siphlonurus quebecensis (Gray Drake) Mayfly Nymph

View 9 Pictures

Collected May 13, 2007 from in
Added to Troutnut.com by on May 18, 2007

Female Siphlonurus quebecensis (Gray Drake) Mayfly Dun

View 3 PicturesThis one hatched in my house after I brought some nymphs home to photograph.

Collected May 18, 2004 from in
Added to Troutnut.com by on January 25, 2006

Male Siphlonurus quebecensis (Gray Drake) Mayfly Spinner

View 10 Pictures

Collected June 2, 2005 from in
Added to Troutnut.com by on May 24, 2006

See 4 more specimens...

Mayfly Species Siphlonurus rapidus

These are sometimes called Adams.

This species may reinforce spinner flights of Siphlonurus quebecensis and Siphlonurus alternatus.

Jargon Defined:

Nymphs: The juvenile, underwater stages of mayflies, stoneflies, dragonflies, and damselflies and other aquatic insects whose juvenile stages are covered by hard exoskeletons. The word can also refer to the fishing flies which imitate these creatures, in which case it is used as a blanket term for flies imitating any underwater stage of an invertebrate (except for crayfish and leeches).

Spinner: There are two winged stages of adult mayflies. They emerge from the water as duns, molt on land (usually) into their fully mature stage, spinners. As spinners, they mate, lay eggs, and die.