This common name refers to only one genus.
These are very rarely called White-Winged Sulphurs.
When the important hatches of Tricorythodes
were first discovered by anglers, Caenis
was given the credit. We now know that the Caenis
mayflies are a different group, smaller and less common in trout streams, and they hatch in the evening instead of the morning.
They very rarely elicit selective feeding, but when they do they're very tough to match because they're often much smaller than size 28. This difficulty has earned them the nickname "Angler's Curse."