**Mayfly Species Diphetor hageni (Little Blue-Winged Olive)**

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Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Baetidae (Blue-Winged Olives)

» Genus Diphetor (Blue-Winged Olives)

» Species hageni (Little Blue-Winged Olive)

Common Names

Match	Common Name
	Little Blue-Winged Olive
	Little Western Olive Quill
	Iron Blue Quill
	Little Iron Blue Quill
	Little Western Iron-blue Quill
	Dark Brown Dun
	Dark Brown Spinner

Pictures Below ↓

This is one of the most important species of the Baetidae family. Previously known as Baetis parvus in the West and its synonym (Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.) Baetis devinctus in the East, it is distributed across the country but most of its fame comes from excellent hatches in the West. Prior to all the species being combined with Baetis tricaudatus, most angling literature considered it the most populous and widespread western species of the Baetidae family.

Dorsal (Dorsal: Top.) abdominal markings on the nymphs used to differentiate the species in these older works have since proved unreliable. The easiest way to tell them apart from B. tricaudatus is their lack of gills on the first abdominal segment. Telling adults apart is equally tough. Duns of D. hageni are typically a little smaller, but their bodies can also be olive, brownish olive and even two toned with thoraxes a shade of brown or tan with paler olivacious abdomens.

Diphetor hageni has two former names used in angling literature, Baetis parvus in the West and Baetis divinctus in the East.

Where & When

Regions: East, Midwest, West

Time Of Year (?): April and May, then another brood in September and October; sometimes another intermediate brood

Preferred Waters: Fertile streams

Hatching Behavior

The nymphs and duns are both important during this hatch.

Spinner Behavior

Fred Arbona in Mayflies, the Angler, and the Trout describes peculiar spinner behavior in this species:

Spinners gather in the mornings or evenings, and their tight swarms can be observed over the banks of the stream. After mating, the spinners suddenly vanish and reappear 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.) on the water.

Nymph Biology

These nymphs are very versatile: cold or warm water, slow or fast water, spring creeks and freestone streams.

Pictures of 1 Mayfly Specimen in the Species Diphetor hageni:

Diphetor hageni (Little Blue-Winged Olive) Mayfly Nymph

View 6 Pictures

Collected July 25, 2019 from Mystery Creek #249 in Washington
Added to Troutnut.com by Troutnut on July 26, 2019

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Jargon Defined:

Abdomens: The rear and usually the longest (ten-segmented in mayflies) portion of an insect's body, to which the tails are attached.

Brood: When a species produces more than one generation per year, each one is called a brood.

Dorsal: Top.

Duns: Mayflies have two adult stages. They first emerge from the water as duns (scientifically known as the subimago stage). They then molt into the spinner (imago) stage, in which they mate and die. Sometimes the word "dun" is confusingly used to refer to a brownish gray color in fly tying materials.

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).

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.

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.

Synonym: A former name of a taxon, usually a species. Entomologists frequently discover that two insects originally described as different species are one in the same, and they drop one of the names. The dropped name is said to be a synonym of the remaining name. These changes take a while to trickle into the common knowledge of anglers; for example, Baetis vagans is now a synonym of Baetis tricaudatus.

Useful References:

Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.

Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.

Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.