The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
I'm not sure, but I've wondered about molting and it doesn't seem like that's what's going on. Molted individuals are usually more of a pale blond color, but I've never seen red on them. When I find a red individual in the sample, it tends to stay that way for as long as I have it.
I'm surprised I didn't see the protruding mandible before...
Paul -
I'm surprised I didn't see the protruding mandible before...
I know you were just using broad descriptive language, but for those readers that may be confused, technically those aren't protruding mandibles, they're palpi which are entirely different parts.
Living individuals of R. impersonata have a decidedly greenish tinge which is most noticeable in the areas which are red in R. sanguinea but this is lost in the dried specimens and probably also in specimens in alcohol. It seems probable that the red pigment of one species and the green of the other are related biochemical substances. It is possible that they have some significance in respiration. The distribution of the two pigments in a similar manner in parts of the body having a thinner cuticle and the fact that the pigment carries through from the nymph and subimago to the imago suggests that it is a blood or muscle pigment rather than part of the external colour pattern.