I’ve got a long list of things that need my attention and from the beginning this blog/journal/whatever you call it was supposed to be a semi-organized/semi-scientific approach to the Southeast Minnesota/Driftless Area.  I have organized some of the better photo’s of the natural insects seen on our streams and included a bit of hatch information for the ones I managed to stumble across. This is an incomplete and on going effort that I hope will grow over the years, it can be found here.

Look for more from the Winona Fly Factory with the coming year and the season changes it holds. With the updated and organized photo galleries I will be able to quickly add and compile images that will help myself and hopefully others tie the flies that make the Driftless Area what it is all about. The hatch information presented is based on a combination of first hand experiences, information from other local anglers who truly know this place and entomology texts I’ve read. If you have anything to add or if I made a mistake please feel free to contact me at: winonaflyfactory@gmail.com

I have effectively found information on all of the species of Caddisfly that the hatch chart from Lanesboro, MN describes. Now the question is how to present the information in a logical fashion, with the Mayflies I broke things down first by one of the four nymphal groups and then from earliest to latest in reference to potential emergence dates. Caddisflies are posing more of a challenge in that there are so many species that for my purposes I will be listing them starting with the earliest in emergence dates and ending with the latest. 

These first three represent the winter/spring emergence, February-Mid May. These should be fairly easy to distinguish on the water, only the last two have coinciding dates and are different in size and color. 

Medium Evening Sedge: (Dolophilodes distinctus) 12-16

• Adult Length up to 12mm
• Wing: Gray-Brown
• Body: Brown
• Legs: Brown
• February emergence

From the family Philopotamidae these are net spinning caddis larva living on the undersides of rocks. They spin a net to filter food from the water. Pupa swim or crawl to the banks or surface to emerge and the females dive underwater to deposit eggs.  Specifically D. Distinctus has a unique trait in that they will produce wingless females in the winter that are noticed running along the snowy banks.  These are going to be found in cleaner cooler well oxygenated water and perhaps less found on a larger warmer stream. Larva look like most free living caddis, like a green/olive worm with a black/brown head with six legs. Color for the larva is going to be harder to determine due to the variety in habitat thus finding them in the wild is important.

Summer Flier Sedge: (Limnephilus submonifer) 10-12

• 13-15mm Average Adult Length up to 20mm
• Wing: Ginger-Reddish Brown
• Body: Ginger-Brown
• Legs: Ginger-Brown
• April-May Emergence

This species of caddis fly is from the Limnephilidae super family that encompasses tube-makers of which there are many, over 56 different genus with each genus potentially having several species. L. Submonilifer are going to be found in much slower water sections, LaFontaine says he found these most in ponds in New Hampshire in much slower water, something to keep in mind. This specific specie builds a stick case in which to live, different from a spun net tube or rock tube.

Little Sister Sedge: (Cheumatopsyche pasella) 14-16

• Adult length up to 10mm
• Wing: Brown-Dark Brown
• Body: Green to Greenish Brown
• Legs: Light-Dark Brown
• Very Short Emergence Early May

Coming from the Hydropsychidae family of net-spinners this is a free living caddis larva. The information I’ve found indicate that the Cheumatopsyche is closely related to the Hydropsyche the main difference is size. The Little Sister Sedge is smaller than its cousin. These specific larva and subsequently adults will be more likely found further downstream in warmer water with higher sediment and algae content.

This information may be flawed or incorrect, I am not an entomologist, however sometimes I wonder why not? I’m sure there are bugs I wouldn’t like. If you think something is incorrect please let me know.

This is the 1st in what may be a long series on Caddis flies. As with the Mayfly Entomology series I did, I will be concentrating specifically on the species within the Hatch Chart that the Lanesboro Fishery put out, you can view it here. Armed with research tools and the chart I will be grouping the species into appropriate groups and posting information on each.  A few things should be discussed though before delving into the specific species of Caddisfly here in Southeast, MN.

I feel that Gary LaFontaine places special emphasis on the pupal state of a caddisfly and because the caddisfly has this stage in it’s development I thought this would be a good place to give some general information on the life cycle of the caddisfly.

Egg’s: Are deposited by female caddisflies some of whom deposit them by diving under the water fully submerging themselves and depositing the egg’s in a good location. Some species of caddis also fully submerge themselves but do it by crawling into the water from any location protruding from the surface. This is a good thing to note if you see concentrations of flies surrounding branches sticking out of the water or rocks.

Larva: Caddisflies exist as a Larva for most of the life cycle and as such these Larva are of great importance to the fly fisherman. As you probably know they come in many shapes and sizes. Anyone who has turned up a rock here has seen them even though they may not have known what they were looking at. Caddis larva live in a few ways, some species live uncased and cling to rocks with a spur or barb that protrudes from the back end of the larva. These typically are longer, green-olive and sometimes extremely bright green in color. Some species build cases from small pebbles weaved together with silk. Some simply weave a shell of silk around them while others build small bunkers in which they fully cover themselves like a small bomb shelter. The picture of the un-cased larva is of the underside and shows the tail which grasps onto rocks well. 

Pupa: When the caddis fly is ready and water conditions are right a larva will begin to change into a pupa. This pupa is different from a rising nymph in that caddis use a thin layer surrounding them which inflates with tiny bubbles to help them rise to the surface. LaFontaine goes into great detail with regards to this process because it was viewed improperly before his diving experiments and observations. The caddis will remain just below the surface after it has inflated its coating for potentially quite some time making this a good condition to imitate. With that LaFontaine used the Dupont product Antron to simulate the bubbles and how trout perceive the light reflected by these bubbles. The pupa remains just below the surface until the fly is about to emerge in which it does so fully able to fly off immediately unlike the Mayflies who must typically hang around the surface drying its wings.

Adult: The adult leaves the water immediately. Caddis flies can be seen in there adult form dancing over riffles and preparing to mate and deposit eggs thus starting the cycle over again.

Once again I will note that I am not an expert but attempting to learn as much as possible specific to the area of Southeastern, MN which may or may not pertain to Southwestern Wisconsin and Notheastern Iowa. I encourage comments which will either point out a flaw in my writing or will provide me with more information.

After work I dawned a set of hip-waders and a rain coat, no rod, no reel, and no fly box just a backpack, camera, and items for research. I drove to a stream that I spent much of my summer on. I figured this would be a good place to start gathering samples. The rain poured down as I walked the stream searching for the areas I wanted to sample. I brought several small mason jars to hold the captives until they could be more closely inspected at home. I stumbled through the water not really able to see the bottom because of the rain obscuring the surface of the water, as a result I almost stepped on a few trout that were held up in places that I hadn’t seen them in the summer months. I used a strainer, the handle broke almost instantly and I was forced to used my arm as a replacement to gather samples from shaken aquatic plants and kicked up substrate. The stream water and rain made me rather cold and wet but I had a hard time quitting. Two hours of taking samples, looking for the specifics I’ve been reading about and I decided to pack it in before catching something nasty.

I wanted to take a semi-scientific approach to this so I labeled my samples with the types of substrate or plant they came from, this to help in the future determine what lives where. I also started a field log with date, time, weather conditions and location. I plan to continue this behavior.

I brought my jars home and after gathering a few house hold supplies I was ready to begin my investigation. I did a rough count of each type of insect caddis, mayfly, scud, and what I believe to be midge pupa (maybe not). I measured in mm. many of the subjects and tried to figure out each species. I was pleased to see that my little stream camera takes decent close up images. 

In addition to the pictures above I found several examples of scuds and non-cased caddis. I believe that the picture labeled Nymph 2 is a Baetis. I compared it to images I have and I am pretty sure, it fits the right size in mm, and the right attribute with regards to the slightly shorter middle tail. I found no burrowers but I think I found both an example of a fast swimmer (Nymph 2 above), and a feeble legged crawler (Nymph 1 above). I found several types of caddis both cased and non. The image on the bottom right is of a caddis larva removed from its protective rock built shell. Note: this is not a tubular shell, it is the kind that looks like a tiny pile of pebbles stuck to a rock.

This was a good time.

p.s. After looking the photo’s over I think Nymph #3 is a Stonefly nymph, thoughts?