Common Names: Hendrickson, small western dark hendrickson
Scientific Name: genus Serratella

Serratellas are not a major hatch on western fly waters, but they can be locally important. They are in the crawler group of mayflies. The nymphs inhabit medium to fast water.

Hatches can begin in July and continue through September. At emergence, nymphs rise to the surface and the dun emerges on the water. Trout may prefer to take the nymphs as they rise, rather than the duns. So observe the hatch carefully and experiment to see what the trout are focused on: rising nymphs, emergers and cripples, or duns.

Spinner falls are in the evening, but are seldom important. If you encounter one you can match it with a Rusty Spinner or similar pattern.


NYMPH COLOR: Dark brown or black with blue or purple tints.

DUN SIZE: 7-8 mm (1/4 to 5/16 in)

DUN COLOR: Wings--smoky gray. Body--brown-olive to red-brown. Legs--cream

SPINNER SIZE: 7-8 mm (1/4 to 5/16 in)

SPINNER COLOR: Wings--clear. Body--darker than dun.

OTHER CHARACTERISTICS: Nymph--three tails of equal length with alternating light and dark bands; light stripe down the back of most nymphs. Dun--cream colored legs. Dun and spinner--three tails.

Click on the fly name to see the pattern. Click on the presentation to learn how to do it.

Nymph A. P. Black 16-18
indicator, tight line, rising nymph medium to fast flows
Hares Ear 16-18
dark brown, black with purple mixed in
indicator, tight line, rising nymph medium to fast flows
Dun Sparkle Dun 16-18
Body: brown-olive, red-brown
standard dry fly runs