Guns and Roses Variant 

Chironomid pupa, as with other nymphs and pupa, trap gas beneath their pupal skin to aid both their ascent and final adult transformation. Early in the emergence, the volume of trapped gas is low and the pupa tend to take on a gun metal grey or pewter color. This variation of John Kent's Guns N' Roses is a great choice for suggesting early staging pupa just above the bottom.