|....................... .................... ...Fly Fishing Yellowstone National Park
New KISS Bug Series - Part 7
Midges are in the Chironomidae family of insects. They undergo complete metamorphosis,
meaning they change from an egg, to a larva, to a papa and finally to an adult. They’re two-winged
insects as adults. Midges are in the Diptera order of insects meaning they have "two wings".
Midges are another important aquatic insect that anglers need to be familiar with. It's a mistake to
think that midges are not an important food item for trout in the freestone streams of Yellowstone
National Park. There are times early in the season and late in the season when imitations of
midges are about the only flies you can fish that catch trout. Of course, this is usually when
inclement weather is occurring. If you happen to be visiting Yellowstone when it turns cold and
most everything else shuts down, you may wish you had some imitations of these small insects.
Midge larvae look like tiny grub like worms. There are two types. There are the ones that burrow in
soft bottoms and there are the free swimmers that hide under rocks, sticks and other debris. Most
of them in Yellowstone are probably burrowers but there are plenty of both types.
When the midge larvae change go into the pupae stage of life, they are most subject to being
eaten by trout. Most of the pupae emerge in the surface film. Often, the pupae have a difficult time
breaking through the surface skim and consequently, changing into an adult. Midge pupae look
quite similar to the larvae except they have a wing pad area that is thicker than the body of the
larvae. The midge pupa is the most important stage of life to imitate with a fly. That's because the
trout can just pick them off when they are trying to get to the surface to hatch as well as when they
are in the surface skim trying to change into the adult stage of life.
The adult midge looks similar to a mosquito. They can be important to anglers during the time they
are mating and depositing their eggs. They are imitated with tiny dry flies.
Copyright 2012 James Marsh