a suborder of the protozoan class of Sporozoa. There are four genera, which include a few dozen species. Haemosporidia are found everywhere, but primarily in the tropics and subtropics. They live parasitically within the red blood corpuscles or the vascular endothelial cells in vertebrates, including man, reproducing there asexually by multiple fission (schizogony). In insects, which serve as vectors of Haemosporidia, they reproduce sexually. Several species of the genus Plasmodium, the causal organisms of malaria, live parasitically in the red blood cells of man.