|....................... .................... ...Fly Fishing Yellowstone National Park
New KISS Bug Series - Part 31
White Miller Caddisfly
Now that I just finished covering the Spotted Sedge, lets go ahead and get to another very plentiful
Yellowstone caddisfly. The White Miller is one of the long-horned caddisflies, so called because its
antennae are long. Because of this and their very light color they are easy to distinguish from other
caddisflies. The antennae are about one and one-half times as long as their bodies. That much identifies
them as a long-horned caddisfly and the other thing that ties them down as a White Miller is the light
cream, almost white color of their wings.
Most species of White Millers prefer weedy, slower moving water. They are also found in moderately flowing
streams, especially if they have heavy weed or other aquatic vegetation. The Madison River, Lower
meadow section of the Gibbon River and the Firehole River has a huge population of these caddisflies.
White Millers are species of the nectopsyche genus of the Leptoceridae family of caddisflies. These are
called the tube case makers. Most eastern anglers have seen this caddisfly, although they exist in trout
streams nationwide. The are very plentiful in many eastern trout streams, including most all of the slower,
weedy trout streams.
In some streams these caddisflies hatch two times a year. I am not sure if they are bi-brooded or if they are
different species of the nectopsyche genus just hatch at different times during a year. In Yellowstone,
there's is a hatch in the Spring and another in the late Summer to early Autumn. I tend to think they are
bi-brooded but again, I'm not positive about that. I do know you will see what appears to the naked eye to
be identical species twice a year. Most hatches last over a long time span during each of its two hatches
and the hatches are usually very prolific.
In Yellowstone streams we have been able to see these caddisflies emerging during daylight hours but it's
always very late in the day. We have been able to catch a lot of trout on our Perfect Fly adult imitation
during the late afternoons and early evenings. Keep in mind this is sometimes between 9:00 and 10:00 PM.
In most eastern trout streams the hatches are very prolific but both the hatch and the egg laying activity
occurs during the night. We have found the banks, bushes and tree fully covered with these caddisflies.
Under those conditions we have caught trout on the Perfect Fly pupa and adult imitations in some eastern
If a hatch is underway, we usually fish the pupa in the early morning and the adults late in the afternoons
but we have found that often, the pupa imitation outproduces the adult in the late afternoons and early
Availability to trout:
Type of water:
Duration of hatch period: