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.


How to Match a Serratella

Hatches are matched from Westfly's database of "standard" fly patterns.

Size 16-18 Hares Ear. Body: brown-olive, red-brown
Size 16-18 Sprout Midge, Film Critic, Hackle Stacker. Body: brown-olive, red-brown
Size 16-18 Sparkle Dun. Body: brown-olive, red-brown


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.