In the photo above -- an unidentified common netspinner found last year in Missoula, Montana.
Entomologists divide caddisflies (Trichoptera) into three different groups: Spicipalpia, Annulipalpia, and Integripalpia. These names refer to the nature of the terminal apex of the maxillary palps on the adults: spica = pointed; annulus = ringed; integra = entire/complete (see Glenn Wiggins, Caddisflies: The Underwater Architects, pp. 12, 107, 123, and 151). With a focus on the lives of the larvae, Wiggins argues that the Integripalpia caddis are the "portable case-makers": the Annulipalpia caddis are the "fixed-retreat-makers" (which make nets for collecting their food): and the Spicipalpia caddis are "closed-cocoon-makers," making special cocoons for pupation. (Wiggins, Caddisflies, pp. 12-28)
In terms of the caddis larvae that we see in our streams, the Spicipalpia group is comprised of the "free-living caddisflies" (Rhyacophilidae), the so-called "saddle case-makers" (Glossosomatidae), and the so-called "purse-makers," or "micro caddisflies" (Hydroptilidae). He argues that Glossosomatids and Hydroptilids are not true case-makers. (For his argument, see, especially, pp. 28-28 and 65-71.)
I will present my photos of caddisfly larvae, by species, in three different entries: 1) the Spicipalpia
families and two of the Annulipalpia families -- the fingernets (Philopotamidae) and the trumpetnet makers (Polycentropodidae); 2) the third Annulipalpia family -- the common netspinners (Hydropsychidae); and 3) Integripalpia -- i.e. all of the case-maker families.
III. Trichopera: Spicipalpia
Rhyacophilidae (free-living caddisflies)
1. Rhyacophila carolina. Size: not given by Beaty; Season: Winter into Spring.
2. Rhyacophila fuscula. Size: large; Season: Fall, Winter, Spring
3. Rhyacophila nigrita. Size: not given by Beaty; Season: Winter and Spring.
4. Rhyacophila glaberrima. Size: 12 mm??; Season: Winter.
5. Rhyacophila ledra/fenestra. Size: 14 mm; Season: Winter and Spring.
6. Rhyacophila sp. (banksi complex?)
1. Glossosoma nigrior. Size: 4-5 mm; Season: Winter and Spring.
dorsal view of case
Hydroptilidae ("purse-makers," micro caddisflies)
1. Hydroptila (?). Size: up to 5 mm; Season: Summer. (Note: I've never seen one larger than 2mm.)
microscope photos of preserved specimen
III. Trichopera: Annulipalpia (in part)
Philopotamidae (fingernet caddisflies)
1. Chimarra. Size: up to 12.5 mm; Season: Late Summer into Early Winter.
2. Dolophilodes distincta. Size: 11-12 mm; Season: Fall and Winter.
3. Wormaldia. Size: up to 14.5 mm; Season: Winter and Spring.
Polycentropodidae (Trumpetnet caddisflies)
1. Polycentropus. Size: up to 25 mm; Season: Spring and Summer.