NITROGEN n.
f the atmosphere by volume. It is chemically very inert in the free state, and as such is incapable of supporting life (hence the name azote still used by French chemists); but it forms many important compounds, as ammonia, nitric acid, the cyanides, etc, and is a constituent of all organized living tissues, animal or…
PUPA n.
nd snails having an elongated spiral shell. Coarctate, or Obtected, pupa, a pupa which is incased in the dried-up skin of the larva, as in many Diptera. -- Masked pupa, a pupa whose limbs are bound down and partly concealed by a chitinous covering, as in Lepidoptera.