Pull just holding head of fragile insect (9)
I believe the answer is:
dragonfly
'insect' is the definition.
(dragonfly is a type of insect)
'pull just holding head of fragile' is the wordplay.
'pull' becomes 'drag' (dragging is a kind of pulling).
'just' becomes 'only' (synonyms).
'holding' means one lot of letters goes inside another.
'head of' suggests taking the first letters.
The first letter of 'fragile' is 'f'.
'only' placed around 'f' is 'onfly'.
'drag'+'onfly'='DRAGONFLY'
(Other definitions for dragonfly that I've seen before include "Large winged insect" , "Insect with two pairs of transparent wings" , "Large hovering insect" , "creature!" , "it wings along" .)