Prophet going round S. American city for insects (10)
I believe the answer is:
mosquitoes
'insects' is the definition.
(mosquito is a kind of insect)
'prophet going round s american city' is the wordplay.
'prophet' becomes 'Moses' (Moses is an example).
'going round' indicates putting letters inside (some letters go around others).
's american city' becomes 'quito' (I can't explain this - if you can you should give a lot more credence to this answer).
'moses' enclosing 'quito' is 'MOSQUITOES'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for mosquitoes that I've seen before include "Flies" , "Irritating fliers" , "Bearers of malaria" , "Carriers of disease" , "Malaria carriers" .)