The mosquitoes spreading Dengue fever in Taiwan are the Aedes (Mainly Aedes albopictus and Aedes aegypti), characterized by their black and white stripes. The Aedes aegypti, which has vertical yellow stripes in the middle and a pair of vertical scales on both sides of the thorax that form the shape of lyre, prefers to stay indoors; while the Aedes albopictus, the one with white stripe down the middle of the top of the thorax, usually lives outdoors.