Fly by night, finally getting directions over Spain (6)
I believe the answer is:
tsetse
'fly' is the definition.
(tsetse is a kind of fly)
'night finally getting directions over spain' is the wordplay.
'finally' says to take the final letters.
'getting directions over' becomes 'sets' (I can't justify this - if you can you should give a lot more credence to this answer).
'spain' becomes 'e' (abbreviation for Espana).
The last letter of 'night' is 't'.
't'+'sets'+'e'='TSETSE'
'by' is the link.
(Other definitions for tsetse that I've seen before include "Disease-carrying fly" , "cause of sleepiness?" , "flies" , "carrier of disease" , "fly across Africa" .)