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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.

Caddisfly Species Hydropsyche californica (Spotted Sedge)

Hydropsyche californica together with Hydropsyche occidentalis (both commonly referred to as Spotted Sedge or Spotted Caddis) are the most important Hydropsychidae in the West. It can also be stated that they are arguably the most important western hatches of any kind, at least to the trout if not anglers. On freestone rivers and streams their numbers can be truly astounding. This is especially so on tailwaters.

Where & when

Time of year : Highly variable; can be found on the water from early spring to early fall, depending on location

Distributed throughout the West, but their concentrations are highest in the West Coast states.

Specimens of the Caddisfly Species Hydropsyche californica

1 Larva
Hydropsyche californica (Spotted Sedge) Caddisfly Larva
Size - 14 mm

Condition - preserved

Habitat - cobble bottom, moderate flow run, at a depth of approx. 1 1/2 feet.

Key Characters - pair of large prosternal sclerites

This is a very common taxon at this location. I collected using a kick net. In life, it is bright olive green ventrally, shading to a dull olive at its dorsal abdominal surfaces. In the hand, the legs, thoraxic regions, and head appear medium chocolate brown. The stark contrast of the thoraxic plate's dark edges and light legs are effects of preserving. The plumouse anal hooks were duck down gray, not the color of the gills as appears in the preserved specimen.

The Lower Yuba River is a good habitat for this species, being a larger river with an open canopy. The Feather River just to the north of the Yuba system also finds H. californica in abundance. The other common Hydropsyche species in the area, Hydropsyche occidentalis, seems to prefer smaller, shaded streams.


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  • LaFontaine, Gary. 1981. Caddisflies. The Lyons Press.
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