GREEN DRAKE
Not as widespread as other insects, green drakes hold a special place in flyfishermen's hearts because they draw large trout to the surface. Green drakes are relatively large and easy to see. They hatch while waters clear after spring run-off. Mimic drakes with the following flies on hook sizes 10-12:

Nymphs: Olive Hare's Ear; Green Copper John.

Emergers: Green Drake Emerger; Quigley's Green Drake Cripple.

Adults: A.K.'s Biot Green Drake; Hairwing Green Drake.

RED QUILL
The red quill is not widespread, but its patterns can simulate other mayflies. When they do hatch, it's usually at midday on warm days. To mimic them, try the following patterns on hook sizes 12-18:

Nymphs: Pheasant Tail (BH and Flashback); Red Quill Nymph.

Emerger: Red Quill CDC Cripple; Red Quill Quigley Cripple.

Adults: Mahogany Sparkle Dun; Red and Blue Quill Dun/Spinners; Rusty Spinner; Red Quill Spinner.

STONEFLIES
A four-year lifespan makes several species of stoneflies available all year, making these meaty morsels a major part of a trout's diet. The salmonfly is the largest stone, but its distribution is limited. Little yellow and golden stoneflies are slightly smaller and widely spread. Late in the evenings and at night, stonefly nymphs migrate to shorelines to crawl out of the water prior to emergence, drawing trout into shallow shorelines to feed. Nymph patterns are often more productive than adult flies. Use hook sizes 4-16 to tie these:

Nymphs: Gold-Ribbed Hare's Ear; Kauffman's Stonefly; Halfback.

Adults: Improved Sofa Pillow: Bird's Stonefly (No. 4-8 for Salmonfly); Yellow and Orange Stimulators.

TRICO
Distribution of the diminutive trico is limited, but they are important to trout wherever they exist, providing food during the hatch and spinner fall. Trico-eating trout can be quite selective because astronomical numbers of tricos blanket the water, lowering the odds that an imitation will be selected instead of a natural. Tie these on size 18-24 hooks:

Nymphs: Pheasant Tail; Trico Nymph.

Emergers: Trico CDC Emerger.

Adults: Trico Poly-Wing Spinner; Trico Comparadun; Trico Sparkle Dun.

OTHER FLIES
The following patterns are successful on most Colorado waters, especially when no hatches are active.

Terrestrials: In late summer into fall, beetles, ants and grasshoppers entice trout as insect hatches diminish. I like them small, 14-18.

Attractors: Royal Wulff; H&L Variant; Humpy (yellow, orange, red) in sizes 14-20.

Nymphs: Copper John (various colors); Prince Nymph; Palomino Midge, in 14-20.

Versatiles: Woolly Bugger (olive, black, purple); Hornberg; Muddler, in 12-16.

MAJOR RIVERS
The hatch chart reflects conditions throughout Colorado, but not specifically for every river or stream. Variations are described below. For hatch information and specific fly patterns, contact local fly shops or guides.

South Platte -- Home to highly selective trout, the South Platte has no salmonflies; the North, Middle and South Forks have green drakes.

Cache la Poudre -- The Poudre has all major insects except salmonflies. It is prime terrestrial water in late summer/early fall.

Arkansas -- It's famous for the Mother's Day Caddis, but don't forget green drakes, tricos and red quills.

Conejos -- A brown drake substitutes for the green drake here. Leave the trico and salmonfly at home.

Rio Grande -- The mid-June salmonfly hatch is a big event on the middle Rio Grande; no tricos here.

Animas -- The Animas is a caddis river; also popular are golden stones and streamers. There are no tricos, green drakes or red quills.

Gunnison -- The once world-famous salmonfly hatch is now restricted to the river below Blue Mesa Dam; no tricos here.

Colorado -- The Colorado hosts a major salmonfly hatch starting in April; PMDs have a pinkish hue. You won't find green drakes here.

Roaring Fork/Fryingpan -- The Fork's most popular hatches are on both sides of runoff: caddis in April/May, green drakes in July; no salmonflies or tricos. The 'Pan has tricos, but no salmonflies.