The midge life cycle is similar to that of the caddis: they live as larvae, are buoyed to the surface as pupae, emerge and deposit their eggs as adults.
The first stage consists of an egg stage. Adult midges mate during flight, and tend to gather in large mating swarms along the waters edge of lakes or streams. Once mating is complete the females fly back over the water to release fertilized eggs by tipping their abdomen in the surface film. The eggs sink to the bottom of the stream.
The larval stage emerges from the egg and begins its life on the bottom of lakes and streams or free living in the water column. Because most midges are poor swimmers, they are often found hiding amongst the aquatic vegetation of the slower runs and flats of the stream. Some species of midges construct small tubes or cases in which they live in. These larval house are oriented upright at the bottom of the stream. Fully developed larva undergo the change into the pupae state. For many species, the final larvae stage occurs with a larval tube or case, which is sealed off while it undergoes the final transformation. Once the pupa is fully developed it breaks free of the old larval casing and begins to rise to the surface of the stream. They produce a gas beneath the abdomen which give the pupa a silvery or mirror appearance that trout will often key in on.
When the pupa reaches the surface film a split forms along the back of the thorax and the adult phase emerges on the surface of the water and immediately flies off. Most pupal emergence, mating usually takes place within-in 24-48 hours, completing its lifecycle.
Prior to midge hatches, larva and pupae become washed into feeding lanes and trout will eat them. The pupae are extremely vulnerable as they kick feebly to the surface and hang suspended beneath the surface film. They are small, but so many are available that trout feed on them eagerly. Trout often feed selectively on midge pupae, but rarely feed selectively on midge larvae or adults.
To fly fisherman, midges constitute the most important group of aquatic Diptera. Fly patterns referred to as midges come in an array of colors and usually range in size from #18-28. It is difficult to determine exactly which species of midges are being imitated, and patterns are not as specific, except in size. Some popular patterns include the Black Midge, Zebra Midge, Blue Dun Midge, Chironomid Killer, Frostbite Midge, Miracle Midge, Grey Midge Pupa, Green Midge Pupa, Blood Midge, and the Snow Fly.
Check out Rick Takahashi & Jerry Hubka book Modern Midges - Tying & Fishing the World's Most Effective Patterns Headwater Books - Stackpole Books, Copyright 2009.
Because trout have plenty of time to look at the pupae, and because the pupae have little or no movement, imitations need to be realistic and cannot rely on motion to suggest life. But don't despair! By looking at four characteristics-- shape, thickness, flash, and color--you can imitate any species of chironomid anywhere in the world.
When a pupa rises towards the surface--the time when it is most vulnerable to trout--its body can be straight or curled, though most are slightly curled. As they move to within an inch of the surface, their body will lie parallel with the surface. Here, only straight-shanked imitations do well.
However, it is quite difficult to tie realistic patterns (without CDC, hackles, etc.) that lie flat in the surface. Here is where creative tying really can pay dividends. A foam-backed fly like Maggie's Midge, which I'll discuss in part two of this article, is one of many creative ways to approach this problem.
The standard rule for tying nymphs is to make the abdomen 50% of the body length, while the thorax is about 40% (with the head composing the last 10%). With chironomid pupae, however, the thorax and head combined are at most 20% of the total body length. The thorax is also not much thicker than the rest of the body. Too many standard patterns make the thorax too thick and too long.
The most common failing of commercially-tied chironomids is that they are too thick. If you capture some naturals, you'll see this at a glance. It's critical to keep your chironomids from looking like bloated summer sausages amongst the naturals.
Guessing the diameter of chironomid pupae is relatively simple, since most species have length-width ratio similar to that of hooks. On a given size dry fly hook (1X fine), the body diameter of a chironomid pattern should be a shade under twice the gauge of the wire.
Many people have trouble dubbing thin bodies, but new synthetic materials such as Frostbite, Superfloss, Krystalflash, Flashabou, Lurex, Nymphskin, and Thinskin can give your fly both flash and a slender profile. Traditional materials like V-rib or Larva Lace can also be used to give thin, segmented bodies.
All chironomids gather gasses under their pupal shuck. This helps them rise to the surface when they emerge. Therefore it is essential to incorporate flash on your fly. I proved this to myself when I fished traditional, no-flash patterns on the same line within eight inches of patterns that incorporated flash. The flies with a Flashabou ribbing (instead of gold wire) caught four times as many fish.
If you use standard wire or tinsel ribs, use a silver color, for it better imitates the gasses. These gasses can also be imitated by using CDC; the CDC traps a bubble of air next to your fly. The bubbles can also be imitated by soaking a dubbed pattern in a liquid floatant, such as Gorilla Proof.
Midges come in more colors than crayons, so to keep it simple let's assume that they only come in black, olive, and red. My rule for picking colors is: muddy bottoms-red, sandy/rocky bottoms-black, weedy bottoms-olive. These are the colors I start with, but the great thing about chironomids is that they are most effective when fished in tandem, so you can experiment with various colors. When these three won't produce, I turn to maroon or orange-brown. There are also some chironomid pupae that have pearly-white bodies, and are aptly named "Phantom Midges."
About 80% of your flies should be red, black, or olive, but tie up a few in unusual colors for those times when fish won't fall for the old standards.
Because of the gasses trapped under the pupal skin, many chironomids appear to be banded in color, such as an alternating red and black. I always carry some banded patterns; I have a little more confidence in them when fish are being snooty about standard patterns.
All chironomid pupae have a tuft of white gills at the head of the insect. I prefer to imitate this with a short tuft of white CDC, because in addition to the color, it gathers a gas bubble like the natural. If you don't want to use expensive CDC, try some white Anton fibers. White foam adds buoyancy and color, but it doesn't give the "fluffy" look of CDC and Anton. I use a white gill on 80% of my chironomid patterns, though occasionally fish prefer flies without them.
If you seine a few chironomids from the water, you'll notice that quite a few of the black larvae you come across will have red butts. This coloration occurs among certain species of "bloodworm" midges. A butt of red Flashabou or dubbing can be easily incorporated into any standard chironomid pupae pattern.
Another thing that most Western tiers miss is that the wingpads of many chironomids turn an orange hue prior to emergence. This sometimes can make a huge difference, and other times the fish couldn't give a rat's ass. So I always tie up some of my standard patterns with an orange Raffia or orange Anton wingpad. Stocked trout, whether they appreciate the added realism or not, seem particularly vulnerable to the orange-enhanced patterns.
The family Chronomidae, the midges, are widespread, abundant, and available. Midges come in a wide range of sizes and color of the larva, pupae, and adults of the same species.
Midge larva have slender, curved bodies with a pair of prolegs just behind the head and at the tip of the abdomen. Pupae have an evenly tapered body with short distinct wing pads at the thorax and a pair of small, paddle like plates at the end of the abdomen. Most species have a clump of short, white filamentous gills on top of the head.
Habitat: Midge species have adapted to nearly every type of aquatic habitat. Pick up a rock, pull up some aquatic plants or grab a handful of silt or mud from the bottom and you will find a midge.
Whether a spring creek, large river or little stream, you can find a midge present.
The Snipe Fly has received little attention from fisherman. This maybe an oversight in certain local areas where the fly can be abundant. Snipe fly larvae range from about ½ to just under ¾ inch long when full grown. They are slender and, like Diptera, have no true legs. Instead they have eight pairs of short, stubby appendages called prolegs along the
underside of the abdomen. Off the rear, a pair of moderately long lateral filaments stidk out like short tails. The front end tapers to a point, and the head, highly reduced in size and hidden within the first thoracic segment, is virtually invisible. Most species are dark olive to rather bright green.
Habitat: Snipe flies are found in riffles of cold-water streams and rivers. To pupate they leave the water and select a damp spot along the bank to dig a hole under the soil.
Blackflies are often called buffalo gnats or reed smuts and are the perpetrators of the frustrating smutting rise. Blackflies are distributed worldwide with more than 150 species identified. The larva and pupa stages are aquatic and prefer swiftly flowing water. Size range from ¼ to 1/8 inch long. Larva look like tiny bowling balls while the pupa look like little tan slippers topped with a crown of slender gill filaments. Adults leave the pupal cases underwater and float to the surface in an air bubble. Mating occurs on land or in the air. Female bite do that they have a blood meal for their eggs. They are multibrood and may have one to six hatches a year.
Size: Range from ¼ to 1/8 inch in length.
Habitat: Blackflies live in all types and sizes of streams and rivers, and many species prefer the same conditions as trout: cold water with moderate to fast currents
Craneflies are probably most familiar to people as a long legged bug that looks like a mosquito The Cranefly family is widespread and it would be rare to find a stream without a few species of craneflies. Full grown larvae may rang from less than ¼ to almost 2 inches. Colors vary from light tan to dark brown. Larvae and pupae are basic in shape – tube like body. Most characteristic of cranefly larvae is the apparent lack of a head – tucked deep in the first thoracic segment. The last segment has a swelling into a round, bulblike shape – often mistaken for the head. Pupae look like segmented tubes with a swollen thorax where the legs and wings pad are tucked together.
Habitat: Cranefly species prefer muddy areas along banks of stagnant backwaters. Some species have adapted to rocky substrate in swift currents of cool streams