Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This wild-looking little thing completely puzzled me. At first I was thinking beetle or month larva, until I got a look at the pictures on the computer screen. I made a couple of incorrect guesses before entomologist Greg Courtney pointed me in the right direction with Psychodidae. He suggested a possible genus of Thornburghiella, but could not rule out some other members of the tribe Pericomini.
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Caddisfly Family Helicopsychidae
See Helicopsyche borealis for details. It is the only important species in the only American genus of this family.
Where & when
In 178 records from GBIF, adults of this family have mostly been collected during June (23%), July (20%), August (15%), May (12%), September (9%), April (8%), and March (7%).
In 103 records from GBIF, this family has been collected at elevations ranging from 195 to 10194 ft, with an average (median) of 3363 ft.
Family Range
Specimens of the Caddisfly Family Helicopsychidae
1 Female Adult
This one keys pretty easily to the Helicopsychidae family, of which there is only one genus in North America, and one species reported in this general area.
1 Pupa
I'm calling this one very tentatively Helicopsyche borealis, with some big caveats that I might be wrong.
It seems to key fairly easily to Helicopsychidae, except at the last couplet in Merritt & Cummins (5th ed) it's supposed to have “anal processes short and straight, each with several mesal setae and 2 long apical setae,” whereas this one has VERY short, straight processes with 3 long apical setae and no mesal ones.
Additionally, the only species of Helicopsychidae documented in this region is Helicopsyche borealis, which is supposed to emerge much later in the summer.
It seems to key fairly easily to Helicopsychidae, except at the last couplet in Merritt & Cummins (5th ed) it's supposed to have “anal processes short and straight, each with several mesal setae and 2 long apical setae,” whereas this one has VERY short, straight processes with 3 long apical setae and no mesal ones.
Additionally, the only species of Helicopsychidae documented in this region is Helicopsyche borealis, which is supposed to emerge much later in the summer.
1 Underwater Picture of Helicopsychidae Caddisflies:
A variety of cased caddisfly larvae, probably mostly Neophylax, have clustered along the backside of a rock in fast water. There seem to be some Helicopsychidae larvae clustered along the bottom, and a few other taxa are mixed in. It's interesting that several larvae have especially large stones placed over the front openings of their cases, perhaps to block the case off for pupation.
It does seem to be the wrong time of year for Neophylax to be pupating, but that was the ID given for one of these which I collected and photographed up close.
It does seem to be the wrong time of year for Neophylax to be pupating, but that was the ID given for one of these which I collected and photographed up close.
Start a Discussion of Helicopsychidae
References
- LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
- Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.
Caddisfly Family Helicopsychidae
Taxonomy
Genus in Helicopsychidae
HelicopsycheSpeckled Peters
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Genus in Helicopsychidae: Helicopsyche