Insect stages (6)
I believe the answer is:
larvae
'insect stages' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for larvae that I've seen before include "Tiny creatures" , "Insects just out of the eggs" , "Insects in immature state" , "Grubs" , "Caterpillars, tadpoles etc" .)