Stonefly - Plecoptera
Members of this group are often confused with mayflies. At rest, adult stoneflies fold their wings flat over their abdomen whereas mayflies usually hold their wings vertically.
Stoneflies are found rarely in amber. In fact, I know of no other stoneflies in Mexican amber. They have been identified in Baltic and one has been ID'ed in Burmite amber. This is the first time I have ever seen an adult stonefly at all.
Stoneflies date back to the Permian and are of interest for their many archaic features.