Insects & springtails

Adult beetles

Chewing mouthparts, abdomen covered by hard wing covers

Larval beetles

Sickle/tusk-like jaws, no clawed prolegs, some with 2 tail filaments, some with tentacle-like abdominal gills. OR, mealworm-like larvae.

Bugs

Beak-like or conical mouthparts, wings may or may not be present

Cased caddisflies

Carries a mobile case (which covers a soft abdomen)

Uncased caddisflies

Soft abdomen, tail has 2 fleshy “prolegs” with hooks, no mobile case

Damselflies and dragonflies

Extendable “jaws” on a hinged structure that folds under the head

Lacewings

Long, needle-like mouthparts. (rare in streams)

Mayflies

Gills along the abdomen, and 3 slender or feathered tails

Springtails

Very small, entirely soft, water-repellent body, sometimes a fleshy tail

Stoneflies

Flattened body form (legs to the side of the body) and 2 slender tails

Other legged insects