Tying to Imitate

The following is a list of all the species of Mayfly that inhabit the waters around me and hopefully a comprehensive list of size and color for both surface dries and subsurface nymphs. The one major piece of advice that Hatches 2 presents is that the best way to catch a trout is to have accurate imitations tied for size first, shape second and color third. The book really emphasizes this point. I hope this helps myself and others. If there is a major discrepancy let me know please.

Dark Hendrickson (Ephemerella subvaria) Reddish brown to tan.  April-May

Natural 10-12mm Dry Flies: 10-12, Nymphs 10-12 Std. length.

Light Hendrickson (Ephemerella invaria) Tan with olive and yellow cast. Late May-June

Natural 7 1/2-9 1/2mm Dry Flies 12-14, Nymphs 12-14 Std. Length

Iron Blue Quill (Paraleptophlebia) Dark gray with maroon cast. Late May-June

Natural 6-8mm Dry Flies 16-18, Nymphs 14-16 Std. Length

Sulfur (Ephemerella dorothea) Orange to cream. Late May-Early July

Natural 6 1/2-7 1/2mm Dry Flies 16-18, Nymphs 16 Std. Length

White-winged Blacks a.k.a. Trico’s (Tricorythodes) Charcoal. July-Sept

Natural 3-5mm Dry Flies 20-26, Nymphs 18 Std. 24-26 Turned Up Eyes.

March Brown (Macaffertium vicarium) Mottled tan and brown. June-Mid July

Natural 14-16mm Dry Flies 8-12 4x long, Nymphs 10 Std. and 10 3x long.

Light Cahill (Macaffertium ithaca) Cream to tan. June-Mid July 

Natural 10-12mm Dry Flies 10-12 2x Long, Nymphs 10-12 Std.

The Hex (Hexagenia limbata) Tan-Dark Brown Late June-July

Natural 16-35mm Dry Flies 6-8 4x Long, Nymphs 4-6 3x Long

Yellow Drake (Anthopotamus distinctus) Creamy yellow Late June-Early August

Natural 13-16mm Dry Flies 8-10 Std, Nymphs 10 Std. & 10 3x Long

White Fly (Ephoron leukon) White Late August-Sept.

Natural 9-14mm Dry Flies 8-12 2x Long, Nymphs 10-12 Std. & 10 3x Long

Little Blue-winged Olive (Plauditus punctiventris) Pale yellow olive Late June-Oct.

Natural 3-5mm Dry Flies 20-28 Turned Up Eye, Nymphs 20-28 Turned Up Eye

Blue-winged Olive (Baetis) Grayish olive to dark olive March-May & Sept.-Oct.

Natural 6-9mm Dry Flies 14-18 Std, Nymphs 14-18 Std.

The Clingers

The Fast Water Clingers Family Heptageniidae

These nymphs all have flat slender bodies, they also all have stronger legs to hold in fast flowing water. All the nymphs except the Epeorus genus have three tails, epeorus having only two. The mayflies that have substantial hatch numbers in S.E. MN are Macaffertium vicarium the March Brown and Macaffertium ithica the Light Cahill. I should note that the names of both of these species have changed from Stenonema vicarium and ithica to Macaffertium after further research demanded the shift in genus. Hatches 2 has them listed as Stenonema.

March Brown (Macaffertium vicarium) 10-12 Mottled tan and brown. June-Mid July

The March Brown is the larger of the two species that in habit Southeastern MN. According to my research the nymphs of vicarium are easily identified by the long tails in addition to the flattened body and strong legs. The tails on vicarium also splay at nearly 90 degrees. These nymphs are on average 16mm in length and are reddish brown. Vicarium move prior to emergence and one should examine rocks in ankle deep fast-moderate water for their presence. One should fish nymph patterns deep near the bottom as these nymphs either crawl or swim close to the bottom to find their emergence site. 

Hatches 2 makes it a point to note that the duns of Vicarium have a wing that slants more than other varieties at a nearly 45 degree angle. Hatching occurs throughout the day from 10am to roughly 6pm during the proper conditions. 

Light Cahill (Macaffertium ithaca) 12-16 Cream to tan. June-Mid July 

There is no picture of an ithaca dun on troutnut.com. I was however, able to find an image of a nymph. It’s interesting to me that troutnut.com has so little information on this species. I will be excited to find samples of these in the wild. 

Hatches 2 clearly states that the nymphs of both varieties here vicarium and ithaca need only be tied in medium and dark brown. Nymphs for ithaca should be tied in size 10-12. I’ve decided that when the mayfly series is over I will be posting a master list with sizes for nymphs and dries as well as color for all species related to S.E. MN. 

Anglers should note that days in June where the weather is cooler due to overcast or rain can produce day long emergence, on hotter days they will be concentrated in the morning. I like the fact that Hatches 2 notes that during this time of the year water levels are usually going down and that you should be careful while wading. 

I like the second image, making me want to try tying nymph with black thread down the hook shank then using perhaps lighter dubbing to simulate the dark center of the nymph.

Looking forward, knowing that the urge is always there, driving by streams because they are out of the way. I have been working on Midges for winter and will continue but in an effort to prepare for the prime season I have been reading up on the Mayfly and in specific the varieties that are of importance to my waters.

The task has been very interesting and makes me wish I had started trout hunting much earlier in the season last year. Seeing naturals will be the best way to talor my flies to what the trout here eat. With out that the best I can do is read. With a few hatch charts for this area I have picked the main species of mayfly in this area to research further.

http://files.dnr.state.mn.us/areas/fisheries/lanesboro/se_mn_hatches_080405.pdf

http://www.troutnut.com/hatch/4/Insect-Ephemeroptera-Mayflies

Hatches 2 is going to be my primary source for specific size and color variations for the species I find in the hatch charts. Along with the specific species they break down into four main categories according to nymphal type.

1. The Crawlers

The Super Crawlers Family Emphemerellidae, The Feeble-Legged Crawlers Family Leptophlebiidae, The Tiny Crawlers Family Tricorythidae and Caenidae

2. The Clingers

The Fast Water Clingers Family Heptageniidae

3. The Burrowers

The Slit Dwelling Burrowers Families Ephemeridae, Potamanthidae and Polymitarcyidae

4. The Swimmers

The Darting Swimmers Families Baetidae, Siphloridae and Metretopodidae.

I like the descriptive terms the book uses to help you remember key information about the characteristics of the real life insect such as “silt dwelling” useful to know where and when you will find these insects on the stream. In posts over the next few weeks I will look at specific species of mayfly in these four categories. It is my hope that posting the important information for my area will help me make much better choices with regards to fly tying. This is how I will prepare for next season without having the experiences I will get next season.