Female mosquito head. Coloured scanning electron micrograph (SEM) of the head of a female mosquito (family Culicidae). The mosquito's head is dominated by its large compound eyes (pink). Sprouting from between its eyes are the large antennae, which are sensory organs. The long thin proboscis protruding from the bottom of the head is used to pierce the skin and suck the blood of an animal host. Only female mosquitoes suck blood. Several mosquito species are vectors for human diseases, including malaria and yellow fever.