Life Cycle = egg, larva, pupa, adult

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Cream and Red Lava, Brown Pupa, Olive Pupa (some with gas in skin), Adults (from trout's view)

Size/Profile Larva:  4 - 15 mm (thin and wormlike with slight segmentation)
Pupa:  4 - 12 mm (short tapered body with fat head / wingcase)
Adult:  4 - 12 mm (thin body, six legs, two gray wings along back)
Colors Larva: red, cream, olive, gray, black
Pupa: Body = olive, brown, cream, red, gray, black  Throax = black
Adult: black, olive, brown, gray, cream
Action Larva: wiggle frantically when disturbed from bottom.
Pupa:  some wiggle as they rise slowly towards the surface via the help of trapped air bubbles under the skin.  The pupa often hang in the surface film while waiting to emerge.
Adult: Often cluster in groups or as a mating pair on the surface.
Habitat Midge larva live in the silty bottom, under rocks, and in mossy areas.  They seem to be more abundant in slower water areas.  They prefer the colder water and are in much greater numbers near the dam but can be found throughout all of the fishable San Juan water.
Notes Midge larva patterns are productive fished near the bottom early in the morning before hatches and in between hatches throughout the day.   The transition from larva to pupa includes a significant shape change and often a big color change which is important to understand when trying to match the hatch.   There can also be dramatic color changes from pupa to adult.  Fish tend to key in on the pupa stage and feed heavily on the helpless pupa near the surface waiting to emerge.  Fish also will key in on the emerging midge on the surface of the water.

Pay attention to detail when fishing the midge hatch.  There are many different types of midges on the San Juan and sometimes there can be several types hatching throughout the day.  You must quickly focus in on the size, color, and stage that the fish are feeding on to be successful and you must also be quick to notice transitions and be ready to change.

Fly Patterns Select Midges under the Fly Patterns link  for recipes and pictures of the patterns.