Consider getting these books...

Fly Fishing Midwestern Spring Creeks, Ross A. Mueller
Flies That Catch Trout, Upper Midwest Year-Round Guide, Ross A. Mueller
Trout Streams of Wisconsin and Minnesota, Jim Humphrey and Bill Shogren
This is a hatch chart for SW Wisconsin....SE Minn should be quite similar.
Mayflies
Blue-winged Olive (Baetis spp.)
Timber Coulee, Black Earth All season, heaviest in May and September
Hendrickson (Ephemerella subvaria)
Timber Coulee, Black Earth, West Fork Kickapoo April through May, when you can find them!
Sulfer Dun (Ephemerella spp.)
Timber Coulee, West Fork Kickapoo, Willow Creek, Big Green Mid May through July
March Brown (Stenonema vicarium)
West Fork Kickapoo Late May through June
Hex, Giant Michigan (Hexagenia limbata)
Black Earth, Willow Creek Late June, early July
Tiny Blue-winged Olive (Pseudocloeon spp.)
Timber Coulee, West Fork Kickapoo, Willow Creek, Big Green July through September
Trico (Tricorythodes spp.)
Timber Coulee, West Fork Kickapoo, Big Green Mid July through September
Caddis
Micro-caddis (Hydroptilidae spp.)
Timber Coulee, Black Earth, West Fork Kickapoo, Castle Rock, Willow Creek, Big Green All season, but not heavy at any time
Grammon (Brachycentrus spp.)
Timber Coulee, West Fork Kickapoo May Little Black (Chimarra spp.) Timber Coulee, West Fork Kickapoo April, May
Tan Caddis May through August Spotted Sedge (Hydropsyche spp.)
Timber Coulee, Black Earth, West Fork Kickapoo, Castle Rock, Willow Creek, Big Green June through mid September
Stoneflies
Yellow Sally, Little Yellow (Isoperla spp.)
All area streams May through August
Miscellaneous
Midges (Chironomus spp.) All area streams All season
Yellow Cranefly All area streams May through August
Black Ant All area streams All season
Black Beetle All area streams All season
Grasshopper All area streams July through September
Cricket All area streams May through September