Champion Sprayon Flying Insect Killer is effective on flying insects such as deerflies, flying moths (millers), gnats (midges), houseflies, horseflies, mosquitoes. It is also effective against crawling insects such as ants, centipedes, earwigs, grain mites, roaches, sow bugs and spiders. It can be used indoors or outdoors to eliminate annoying flying insects. Outdoors, for best results, spray directly on crawling insects.