In March and early April, the bluewing olive, or Baetis, mayfly is common throughout trout country.    From Wordnik.com.  [Field and Stream Guide: 50 Ways to Catch Spring Trout] Reference

This fly is easily distinguished from the bluewing olive by its larger size, brown mottling, and raked-back wings.    From Wordnik.com.  [Field and Stream Guide: 50 Ways to Catch Spring Trout] Reference

Mercer's Poxyback Baetis nymph is a great imitation of the midget bluewing olive mayflies that hatch in most areas in August.    From Wordnik.com.  [10 Tactics For Catching Late-Summer, Low-Water Trout on Small Flies] Reference

A size 18 or 20 Parachute Adams or Parachute Black Gnat, or a Griffith's Gnat in sizes 18 to 22, will cover the occasional hatch of midges or, on some rivers, bluewing olive mayflies.    From Wordnik.com.  [Fly Fishing for Trout in Winter] Reference

The white breast and light underwings-especially on drakes-are a good clue when the birds are overhead or twisting and turning, and these help distinguish between greenwing al and the bluewing variety.    From Wordnik.com.  [Field Guide: Know Your Waterfowl] Reference

Productive flies early and late in the season are typically small: bluewing olive emergers in sizes 18-28, GT Triple-Double dries in sizes 12-16 (see page 94), plus ant, midge, and scud patterns from size 16 downward.    From Wordnik.com.  [John Merwin Fishes America's Best Tailwater: Utah's Green River] Reference

Early fishing in spring creeks and tailwaters can involve a lot of nymphing, but hatches sometimes come off ahead of schedule in the warmer water, especially those of small aquatic insects like midges and the miniature, drab mayflies that flyfishermen call bluewing olives.    From Wordnik.com.  [John Geirach's Tips for Catching Early-Spring Trout] Reference

They are joined by a smattering of adult bluewing hens that either didn't nest or lost their clutches or ducklings early and didn't attempt renesting.    From Wordnik.com.  [chron.com Chronicle] Reference

You might even pray for a light snowfall — that’s the sort of cloudy weather that brings on intense bluewing olive hatches and rising trout.    From Wordnik.com.  [Dry Flies in January] Reference