Snakes by the Nile (4)
I believe the answer is:
asps
'snakes by the nile' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for asps that I've seen before include "Egyptian cobras" , "Poisonous creepers" , "Small vipers" , "Poisonous snakes" , "poisonous things" .)