Blue-winged Olives
Baetis
Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
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As far as I can tell, this species has only previously been reported from one site in Oregon along the Columbia gorge. However, the key characteristics are fairly unmistakable in all except for one minor detail:
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
— 4 small yellow spots on frons visible in photos
— Narrow occipital spinule row curves forward (but doesn’t quite meet on stem of ecdysial suture, as it's supposed to in this species)
— Short spinules on anterior margin of front legs
— Short rposterior row of blunt spinules on abdominal tergae, rather than elongated spinules dorsally
I caught several of these mature nymphs in the fishless, tiny headwaters of a creek high in the Wenatchee Mountains.
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Stonefly Family Leuctridae (Needleflies)
Leuctra is the only genus of any known importance to trout anglers. Their wings are rolled to a needle-like point; hence the common name, needle flies.
Where & when
In 70 records from GBIF, adults of this family have mostly been collected during June (21%), March (20%), February (14%), April (11%), May (11%), August (10%), and July (6%).
In 12 records from GBIF, this family has been collected at elevations ranging from 52 to 4203 ft, with an average (median) of 2559 ft.
Family Range
Specimens of the Stonefly Family Leuctridae
4 Adults
This is one of rarest stoneflies in western Montana. It is a bit unusual that it is fairly abundant in a handful of streams that empty into the east side of Flathead Lake. A very beautiful bug.
Members of the family Leuctridae are usually easily identified to family due to the "rolled" wing. They are small, nearly 1/4 " in length, black in color and emerge in early spring.
Start a Discussion of Leuctridae
References
- Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.
Stonefly Family Leuctridae (Needleflies)
Taxonomy
Genus in Leuctridae
Calileuctra
0
0
LeuctraNeedleflies
0
0
MegaleuctraNeedleflies
1
3
Moselia
0
0
Paraleuctra
1
1
PerlomyiaNeedleflies
2
4
Zealeuctra
0
0
2 genera (Despaxia and Pomoleuctra) aren't included.