**Mayfly Species Labiobaetis propinquus (Tiny Blue-Winged Olive)**

Mayflies

Caddisflies

Stoneflies

Taxonomic Navigation -?-

Kingdom Animalia (Animals)

» Phylum Arthropoda (Arthropods)

» Class Insecta (Insects)

» Order Ephemeroptera (Mayflies)

» Family Baetidae (Blue-Winged Olives)

» Genus Labiobaetis (Tiny Blue-Winged Olives)

» Species propinquus (Tiny Blue-Winged Olive)

Common Names

Match	Common Name
	Tiny Blue-Winged Olive
	Little Blue-Winged Olive
	Little Western Iron-blue Quill
	Iron Blue Quill
	Little Iron Blue Quill
	Slate-Winged Olive

This species was previously known as Baetis propinquus, a name from older nomenclatures and angling literature familiar to many western anglers. Prior to its current listing, it did a brief stint in the genus Pseudocloeon. The irony is that though this species has hind wings, it was the last species remaining in Pseudocloeon (before the genus recent Nearctic taxonomic demise) which was best known for its species lacking hind wings as an identifying character.

Though it has a national distribution its most important hatches occur in the West, usually hatching between the larger broods of Baetis tricaudatus. Western anglers experiencing a hatch can easily confuse them with the larger Baetis bicaudatus as both nymphs appear similar with only two tails. Besides size, the adults can be separated from bicaudatus (with the help of a little magnification) because L. propinquus lacks acute costal projections (

The costal projection of a Baetidae dun.

Costal projection: A bump or point sticking up from the front margin of an insect's wing, usually the rear wing of certain mayflies. It is sometimes called a costal process.) on its tiny hind wings. Conversely, the presence of hind wings and lack of conical mesonotal projections (Conical mesonotal projection: small cone shaped spike sticking up from the top and front part of the middle thorax segment.) makes them easy to tell from the more common and equally tiny Acentrella turbida.

Where & When

Regions: Midwest, West

Time Of Year (?): Main broods in July and October

Nymph Biology

Current Speed: Fast or slow; best in slow

Substrate: Variety; best in weeds

Fred Arbona writes in Mayflies, the Angler, and the Trout that this species is found in many habitats but is only abundant in slow, weedy streams.

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Jargon Defined:

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

Conical mesonotal projections: small cone shaped spike sticking up from the top and front part of the middle thorax segment.

The costal projection of a Baetidae dun.

Costal projections: A bump or point sticking up from the front margin of an insect's wing, usually the rear wing of certain mayflies. It is sometimes called a costal process.

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).

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.