Tiny arachnids (5)
I believe the answer is:
mites
'tiny arachnids' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mites that I've seen before include "Times (anag.)" , "tots?" , "little children" , "Minute arachnids that infest animals and stored foods" , "Small arachnids" .)