Remember, even though dry fly fishing is fun and attractive, trout do 90% of their feeding under the surface of the water. Probably close to 70% of their total diet comes from eating the sub-surface forms of the four aquatic insect species 1) Mayflies 2) Stoneflies 3) Caddisflies 4)Midges. The most effective fly fishing method to catch trout is to fish with nymphs!

When these nymphs hatch, the mayfly looks like tiny sailboat, the stonefly adult is big and has two sets of wings, an adult caddis looks like moth with tent-shaped wings and an adult midge has a mosquito-like appearance and is very small.

Time Line for Important Fly Hatches for the Bozeman Area

May	Caddis	ElK Hair Caddis, Parachute Caddis size 14
	March Brown	Adams, Dark Cahill size 10
	Baetis mayfly	Parachute Adams, Blue Wing Olive size 16
June	Salmon Fly	Fluttering Stonefly, Sofa Pillow size 2 & 4
	Golden Stonefly	Golden Stonefly size 8
	PMD mayfly	Light Cahill, Parachute Cahill size 16
	Caddis	Same caddis patterns
July	Caddis, PMD's	Same caddis patterns, same PMD patterns
	Attractor dry flies	Royal Wulff, Royal Trude, Stimulator size 12-14
August	Hoppers	Dave's Hopper, Parachute Hopper size 6-10
	Attractors, caddis	Same attractor dry flies, same caddis
September	Hoppers, attractor dries, streamers, baetis late in month	Same hoppers, same caddis, Wooly Buggers, Sculpin imitations, Spruce Flies size 2-6, Same attractor dry flies, same Baetis Patterns only in smaller size 18
October	Baetis mayfly, streamers for browns	Same Baetis, same streamers
November December January February	Mostly nymphs. Adult midges produce some dry fly activity.	Prince nymphs, stonefly nymphs, Hare's Ear, Fox Squirrel nymph, Lightning Bug nymph nymphs in sizes 6-12 Griffith's Gnat in size 18-20 is excellent Adult midge pattern
March April	Continued nymph fishing, adult midges and beginning of Baetis mayfly hatch	Same nymphs, same midge patterns, same Baetis patterns