Caddisfly larvae of this family can easily leave and re-enters their cases. I caught two of them playing musical chairs or something with this one... funny!
Phryganeidae Caddisfly LarvaView 5 PicturesThis "specimen" is actually two caddis larvae fighting each other over a case. The case is a hollow tube; one larva would go in the back end, presumably bite the other, and chase it out. The invader crawled forward into the case while the other one fled, and then it went around to the back and bit the first one. They did this several times, and I recorded it on video.
Baetisca laurentina (Armored Mayfly) Mayfly NymphView 3 PicturesI took a few group picture of a bunch of Baetisca laurentina nymphs to show the degree of individual variation in size, color, and shape that can occur within the same species in the same pool of the same river. This variation is one important reason why trout are forgiving of some small degree of variation in our imitations--the naturals themselves vary, too.
Siphloplecton (Pseudo-Gray Drakes) Mayfly NymphView 3 PicturesThis nymph has double front tarsal claws (Tarsal claw: The claws at the tip of the tarsus, on an insect's "foot.") and double gills on the first three abdominal segments. This one has a distinct dorsal (Dorsal: Top.) stripe.
Ephemera simulans (Brown Drake) Mayfly NymphView 2 PicturesHere's an unusually small early instar (Instar: Many invertebrates molt through dozens of progressively larger and better-developed stages as they grow. Each of these stages is known as an instar. Hard-bodied nymphs typically molt through more instars than soft-bodied larvae.) nymph.