The larvae of many caddisflies, Order Trichoptera, make cases of sand or bits of vegetation, arrange into a case that ranges from random looking to more uniform to very ordered. The larva of each case-making species makes a characteristically shaped case.

The larvae eventually seal the case and pupate under water. When mature, the pupa chews its way out of the case, swims to the surface and crawls onto a rock, where the winged adult emerges.

I found the log-cabin pupal cases, Brachycentrus sp., with their surprisingly square cross section, attached to a log near the shore of the Dungeness River (slides 1-7). The larger case measured about 12 mm in length and 1 - 2 mm on a side. One case had a hole in the side, the other was intact. Both were dry and very hard.

The family Brachycentridae includes of 37 North American species 33 of which are in two genera, Brachycentrus and Micrasema.

Caddisfly larvae can be forced to use unusual materials for their cases. French artist Hubert Duprat induced caddisfly larvae to build jewelry with gold and precious and semiprecious stones. (See Cabinet Magazine Online - Trichopterae)