The yellow-fever mosquito, Aedes aegypti (L.), when released in a crossbox composed of 5 compartments, preferred to rest in a surface that was highly infrared reflective. When released in a room with 2 Communicable Disease Center miniature Jig-ht traps, one radiating white light and the other infrared, most of the mosquitoes collected were taken ill the infrared trap. When released in total darkness, the mosquitoes were attracted to locate an infrared source. Blood-fed females and mated mosquitoes of both sexes appeared less attracted to infrared than when unmated or honey fed.