1. Troutnut Forum
›
2. Get Bugs Identified
›
3. Chimarra larvae and pupae

There's been a fairly large emergence of Chimarra here over the last few days so I thought I'd try and document some of the larval and pupal stages. The larvae were identified to genus using Merritt. Cummins and Berg (2008). Pupae were identified to family with MCB. Association between larvae and pupae was done by identifying the prepupa as Chimarra using the extension on the forecoxa and the asymmetrical notch at the front of the head. Pupae were associated by the same features in the sclerites contained in the pupal cocoon. Don't know the species. I've collected some adults but haven't gotten around to attempting to identify them to species.

Anyway, here's way more photos than you probably want to see.

Never too many photos, Mark! :) Your pupa photos are the best I've seen of these little guys...

Look for a projection on the clasper's dorsal margin. My suspicion is there is one, which would point to C. utahensis. I believe it's the only species I've run into on our trout waters out here. They're very common in many places but rarely (if ever) important in my experience. This time of year you can bust them out of the damp riparian bushes at the margins, but never seem to see them on the water.

I really enjoy all of the great photographs on this site. They are very helpful.

Kurt - I'll Keep C. utahensis in mind when I check out the adults. Don Burdick's site has some great illustrations of Trichoptera genitalia drawn by Shannon Bickford which include several species of Chimarra from California. Whichever species they are you're right about them being very common. The adults are thick on streamside bushes right now, especially in the early morning. I've netted them low on the water in the evening, mostly females so I suspect they're in the process of laying eggs. Seems like fish would take advantage of them in the larval stage if they're part of the drift and I imagine the pupae would be vulnerable when they emerge but it would probably just be luck to happen upon them then.

As to the photos, they could be better, the pupae seem to be either too light or to dark (depending on the developmental stage) to get really good detail. I'm going to have to fiddle with lighting. I usually just photograph them in natural light (something there's usually plenty of in California).

Bruce - Looks like a sulphur to me.

Low on the water or low over the water? I've observed the latter many times but don't remember the former. As for the pupae, you may be right. Small dark attractor nymphs are as effective as anything else this time of year when nothing else is going on. My suspicion is they trickle off most of the day rather than engaging in mass emergencies that would tend to get the fish honing in on them. They are usually competing with other species for Mr. Trout's attention as well which is another important factor. Out West the Spotted Sedges, late Grannoms, Saddle Case larvae and a few others usually take center stage.

Low over the water. I've never seen them on the water.

Gorgeous photos! Thanks.

I bet an imitation wax worm would do the trick for these guys.

Louis-

Glad you enjoyed them.

Feathers5-

I think it might work well providing the size and coloration were right. Actually, those might work well imitating a lot of caddisfly pupae.