October caddis question

Pat Lat

Mad Flyentist
So I always seem to find two different bugs, or at least I think they're different, when I am looking for good shots of october caddis'.

The first being ones that I see on most rivers in the fall are large dark winged, bright orange abdomen and fuzzy thorax. This is what I envision when october caddis comes to mind.

The second is a more slender bug, rusty colored body and wings with not much variation in color throughout the entire body. I see pics of these online being called an october caddis but they dont seem the same. Ive also seen this bug at my house, which is no where near a river that I would normally think holds a population of october caddis, only a few small creeks.

There are pics of both on google images.
Maybe you could shed some light on this for me, I thought maybe male/female of the same sepcies. Or maybe there are just two types.

Patrick Latimer


Staff member
Hi Pat,

Please provide a link to a decent macro photo of the "more slender bug, rusty colored body and wings with not much variation in color throughout the entire body" which you described. That way I can probably identify it.



Canyon Lurker
i think i know what your talking about. on most all waters that i come across october caddis on ive also seen another big caddis that hatches around the same time as well. as far as i know its a different bug.

Pat Lat

Mad Flyentist



these are the slender ones, the fly in the middle was tied by graham owen, and he also refers to it as an october caddis.

Pat Lat

Mad Flyentist
The ones Ive seen "hatch" at a river were more like these. I just got all the pics off google, there wasn't a good pic of the underside but the abdomen is very orange


Staff member

The two most recent caddisfly photos you posted are what flyfishers (in the Pacific NW) refer to as October Caddis, and are of family Limnephillidae (Northern Caddisflies) and genus Dicosmoecus.

With regard to the earlier photos you posted:

#1 - Haven't yet identified it, but it's not of genus Dicosmoecus.
#2 - Imitations aren't identifiable. ;)
#3 - Haven't yet identified it, but it's not of genus Dicosmoecus.

Pat Lat

Mad Flyentist
yeah i put that one in there to show that some fly fishers call that bug an october caddis, thats his realistic october caddis imitation. if you saw his realistic impressions of other insects you'd be able to identify them.;)


Active Member
Another Limnephillid which hatches in the late summer and fall is Onocosmoecus, sometimes called (surprise) Late Summer Sedge. Until 1955 all species of Onocomoecus were considered to be members of the genus Dicosmoecus and were so listed. Two species are O. frontalis and O. unicolor, the latter described by Gary La Fontaine as "... an even cinnamon shade all over, with virtually no patterning on the antennae, wings, body, or legs. It is a common caddisfly in small to large rivers as well as lakes throughout the Northwest. Adults are on the wing from mid-August to late October."

I've seen these on the Stillaguamish in the fall as well as somewhat earlier in the year at Lake Chopaka.


Staff member
Hi Preston,

Yes, Onocosmoecus unicolor is likely the caddisfly that Pat Lat was describing. Incidentally, it appears as a late-summer to early-fall ememger on my WA Aquatic Insect Emergence Chart. Here is a photo of one, which was taken by (professional entomologist) Bob Newell from the Touchet River in SE WA in early October of 2011:

The real October caddis look much larger than those first pics. Man, when those things start smacking down on the water(to lay eggs?), everything on the river can't help but take notice.

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