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Animal Phylum Arthropoda (Arthropods)

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

Class in Arthropoda
ArachnidaMites and Spiders	0	1
CollembolaSpringtails	0	0
Crustacea-MalacostracaCrayfish, Scuds, and Sowbugs	0	10
Crustacea-Maxillopoda	0	0
InsectaInsects	0	114

Common Name

Match	Common Name
	Arthropods

Pictures Below ↓

This is page 115 of specimens of Arthropoda. Visit the main Arthropoda page for:

The behavior and habitat of Arthropoda.
122 underwater pictures of Arthropoda.

Pictures of 1243 Arthropod Specimens:

Specimen Page:1...114115116...125

Ameletus (Brown Duns) Mayfly Nymph

View 6 PicturesI spent (Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.) ages trying to identify this one but ultimately couldn't narrow it down to species. I'm guessing it's either a species that has not yet been reported from Idaho or a species with some variation in characteristics not accounted for in the current key (Zloty 1997), which is only for Alberta but happens to contain all the species documented in Idaho except for one (which is rare and only in a different part o the state from this one).

Here are my raw notes from the microscope session:

8. Ameletus nymph (genus 100 % based on mouth parts under microscope)
1. This is probably a species with the nymph either not described yet or not reported in Idaho (or Alberta).
2. There is a key to the species of nymphs in Alberta (Zloty 1997) which includes all but one (A. tolae) of the species listed in Idaho by IDFG (https://idfg.idaho.gov/species/taxa/8607), and A. tolae is only listed from one drainage in north-central Idaho. So my specimen should be in that key. However, it doesn’t fit any of them.
1. The antennae are pale with brown at the apex (Apex: The uppermost, outermost, or culminating point; the tip.). This doesn’t fit any of the species they described.
2. The labrum (Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.) is almost completely dark brown, maybe a bit paler toward the apex (Apex: The uppermost, outermost, or culminating point; the tip.).
3. Following the key in Zloty 1997 basically rules out every species reported in Idaho except for tolae, which would be outside its range:
1. Couplet 1 : There definitely aren’t strong ganglionic markings on sternites (

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.) 2-8 (100 % rules out similior and celer) —> 3
2. Couplet 3 : Posterior (Posterior: Toward the back of an organism's body. The phrase "posterior to" means "in back of.") margins of sternites (

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.) 6-8 lack large spines (80 % sure) but other characteristics rule out the species if there were spines (validus, oregonensis, subnotatus) —> 6
3. Couplet 6 : Mesal (Mesal: Toward the middle.) gill extension present, but pretty slim… similar to Fig. 23B or 23G —> 7
4. Couplet 7 : Obviouly gos to 8
5. Couplet 8 : Small size and time of year rules out velox, tergite (

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) patterna and gill shape rules out pritchardi (which is not reported in Idaho anyway). Additional features (antennae, labrum (Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.) color) rule out a small velox.
6. Backtrack to call the mesal (Mesal: Toward the middle.) gill extension “well developed” —> 9
7. Couplet 9 : Tail coloration obviously —> 10
8. Couplet 10 : Supposing it’s a small specimen of a “larger species” leads to 11, in which femora (

The femur of this Isonychia bicolor mayfly spinner is highlighted in red.

Femur: The main segment of an insect's leg close to the body, in between the tibia and the trochanter.) coloration and timing rule out vernalis, and color pattern rules out bellulus. Mesal (Mesal: Toward the middle.) extension on gills from species description very conclusively rules out bellulus. Therefore, calling it a “smaller species” is the correct path —> 12
9. Couplet 12 : Sternites (

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternite: The bottom (ventral) part of a single segment on an insect's abdomen.) without well-defined longitudinal stripe —> cooki. However, tergite (

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.) color patterns don’t even come close to matching ANY of the 3 species from this point on (cooki, sparsatus, suffusus). From the species descriptions:
1. cooki: Antenna and labrum (Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.) colors don’t fit. Mesal (Mesal: Toward the middle.) extension should be larger and tracheation lighter, to be this species.
2. sparsatus: Antenna and labrum (Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.) colors don’t fit. Mesal (Mesal: Toward the middle.) extension should be larger. Postero-lateral (Lateral: To the side.) spines should be very prominent, not barely noticeable.
3. suffusus: Also bad fit to antenna and labrum (Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.) colors, mesal (Mesal: Toward the middle.) extension, and especially gill tracheation.

Collected August 4, 2020 from Green Lake Outlet in Idaho
Added to Troutnut.com by Troutnut on August 20, 2020

Stenacron (Light Cahills) Mayfly Nymph

View 2 Pictures

Collected August 8, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 18, 2006

Formicidae (Ants) Ant Adult

View 2 PicturesThese are very large carpenter and a common terrestrial (Terrestrial: Insects which live on land and are fed on by trout only when they incidentally fall into the water are known as "terrestrials" to fly anglers, and they're very important in late summer.) insect along mountain trout streams

Collected June 6, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on June 26, 2011

Ephemerellidae (Hendricksons, Sulphurs, PMDs, BWOs) Mayfly Nymph

View 3 PicturesThis is a really really really really tiny mayfly nymph. It has gills on abdominal segments 3-7 in the characteristic orientation for the Ephemerellidae family, and it has no fain tail as best I can tell, just uniform tail coverage with small black hairs of equal length. I think this one's too young to identify.

Collected March 10, 2004 from unknown in Wisconsin
Added to Troutnut.com by Troutnut on January 19, 2006

Plecoptera (Stoneflies) Stonefly Nymph

View 3 PicturesThis is a really small stonefly adult, about 3/8 of an inch body length.

Collected April 28, 2004 from the Namekagon River, below Lake Hayward in Wisconsin
Added to Troutnut.com by Troutnut on January 25, 2006

Male Isoperla fulva (Yellow Sally) Stonefly Adult

View 2 PicturesThese Isoperla are loaded with red parasitic mites.

Collected June 6, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on June 26, 2011

Maccaffertium terminatum Mayfly Nymph

View 1 PicturesThis is a subspecies (Subspecies: Entomologists sometimes further divide a species into distinct groups called subspecies, which have two lower-case words on the end of their scientific name instead of one. The latter is the sub-species name. For example, Maccaffertium mexicanum mexicanum and Maccaffertium mexicanum integrum are two different subspecies of Maccaffertium mexicanum.) M. terminatum terminatum, formerly called Stenonema. Found mostly in larger rivers in western Montana. This is an immature nymph.

Collected November 23, 2005 from the Flathead River-lower in Montana
Added to Troutnut.com by Bnewell on June 26, 2011

Male Epeorus albertae (Pink Lady) Mayfly Spinner

View 2 Pictures

Collected June 29, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on June 29, 2011

Male Rhithrogena robusta Mayfly Spinner

View 3 PicturesThese specimens were collected from a mating swarm from the east branch of the North Fork of the Touchet River, upstream from the Bluewood Ski Area turn.It was a sunny warm day, mating swarm as 4-8 ft. above this small stream. Four male spinners were collected.Stream photos were taken.

Collected July 15, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on July 15, 2011

Male Tricorythodes (Tricos) Mayfly Spinner

View 3 PicturesI collected these males about 9:30 AM, air temp. about 68 degrees F. The males were flying about 3 ft above the stream flying up and down the stream rather than the typical vertical swarm you see with most mayfly males. The males are black and the females are a green color due to the eggs they are carrying. They do not live very long which is typical for small bodied mayflies. They do not fly during windy conditions. I suspect these are Tricorythodes minutus.

Collected August 12, 2011 from the Touchet River in Washington
Added to Troutnut.com by Bnewell on August 12, 2011

Specimen Page:1...114115116...125

Jargon Defined:

Apex: The uppermost, outermost, or culminating point; the tip.

The femur of this Isonychia bicolor mayfly spinner is highlighted in red.

Femora: The main segment of an insect's leg close to the body, in between the tibia and the trochanter.

Labrum: The platelike structure forming the roof of the mouth of insects; the upper lip.

Lateral: To the side.

Mesal: Toward the middle.

Nymph: 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).

Posterior: Toward the back of an organism's body. The phrase "posterior to" means "in back of."

Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself.

One sternite of this Isonychia bicolor mayfly spinner is highlighted in red.

Sternites: The bottom (ventral) part of a single segment on an insect's abdomen.

Subspecies: Entomologists sometimes further divide a species into distinct groups called subspecies, which have two lower-case words on the end of their scientific name instead of one. The latter is the sub-species name. For example, Maccaffertium mexicanum mexicanum and Maccaffertium mexicanum integrum are two different subspecies of Maccaffertium mexicanum.

One tergite of this Isonychia bicolor mayfly spinner is highlighted in red.

Tergite: The top (dorsal) part of a single segment on an insect's abdomen when it consists of a single chitinous plate (sclerite), or an individual sclerite if the segment has more than one.

Terrestrial: Insects which live on land and are fed on by trout only when they incidentally fall into the water are known as "terrestrials" to fly anglers, and they're very important in late summer.