The tsetse fly is best known as the vector for the trypanosome parasites that cause sleeping sickness and a disease in livestock called nagana. But its biology is quite unusual. Both sexes feed solely off blood, whereas many blood-sucking insects supplement blood meals with nectar. And females give birth to live young that have been nourished by specially produced milk. Now, the genome sequence and studies of gene activity in various tissues have uncovered the fly's special repertoire of proteins for procuring, filtering, and packaging the blood and for viviparity. They also help clarify the fly's relationship with microbes residing in its tissues. These insights should lead to better control strategies to protect the 70 million Africans at risk for sleeping sickness.