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.
In 52 records from GBIF, adults of this genus have mostly been collected during June (60%), May (33%), and July (6%).
In 33 records from GBIF, this genus has been collected at elevations ranging from 20 to 5614 ft, with an average (median) of 2356 ft.
A hundred or more cases might be stacked in layers on the underside of a particular rock. When the emergence period begins the pupae pop continually from this area. They escape from the cocoon and wash out from under the rock, creating a food line for trout on the downstream side of the pupation site. During the peak evening hours the emerging pupae may create feeding situations in only a small part of the stream. They attract trout into these prime zones (which fly fishermen can find beforehand by searching for the clusters of pupae).
Time of day: Evening
Substrate: Silt, sand, or gravel
Environmental tolerance: Prefers cool streams
Shelter type: Horn-shaped sand and gravel cases