Which one of the following is a stomach poison for the larvae of insects of medical importance?
Insecticides are substances used to kill insects.
They are contact poisons,stomach poisons,fumigants. 
Stomach poisons are those which when ingested cause death of the insects. 
Examples are paris green and sodium flouride. DDT and pyrethrum are synthetic and natural contact poisons respectively. 
Parks textbook of preventive and social medicine.K Park.
DDT
Paris green
Pyrethrum
Antilarva oil