.......................  ....................  ...Fly Fishing Yellowstone National Park
05/14/12

New KISS Bug Series - Part 18

The Little Black Caddisflies
Introduction










The Little Black Caddis hatch, called the Mother's Day Hatch by many, is both an early season hatch and a
late season hatch.  That's because of the two different species found in the park - the
occidentalis, the
early season hatch and the
americanus, the late season hatch. The early season hatch is by far the best
of these two hatches provided it doesn't occur during the Spring runoff. This isn't uncommon for this to
happen. It's also almost completely unpredictable. Although we think the runoff is going to happen very
early this year due to warm weather, it could happen and be over prior to the emergence of Little Black
caddis in many areas of the park.

These insects should be hatching when the season first opens and continue through June. The later
season hatch usually occurs in the last part of August and early September but they are present in less
quantities and only in certain streams, mainly the Yellowstone River, but they also exist in many other
streams to some extent.

So far, our early season trips to Yellowstone have been interrupted in the first part of the season by the
runoff. I can only remember one trip where we caught the hatch going full steam. We were able to catch
lots of trout that year from the Little Black Caddis hatch. Other years have been hit and miss, mostly miss
due to runoff conditions. In spite of that, we always find some hatching in some small streams and we have
also even been able to catch a few during the egg laying when the water was still high and off color from
the runoff. The bottom line is I wouldn't want to be fishing Yellowstone National Park, or any of the other
locations in the area, in June without imitations of the pupae and adults. It can provide fantastic fishing
opportunities for those that recognize the hatch and know how to fish it.  
Copyright 2012 James Marsh
Little Black Caddis:
Species:                             
Type:                                  
Availability to trout:             
Hook Size:                          
Numbers:                            
Distribution:                        
Type of water:                    
Emergence time:                
Duration of hatch period:

Brachycentrus occidentalis, B. americanus
Cassed Caddis (Short-horned Caddis)
Excellent
16/18
Heavy
Widespread
Moderate to slow - smooth and broken surface
Afternoons
Medium