A presumptive culicine host of the human malaria parasites

IN controlled experiments with Culex bit” niorhynchus carried out during the past seventeen months, we have observed what we are unable to distinguish from the complete cycle of development of the parasites of benign and sub-tertian (malignant) malaria in laboratory-bred females fed on gametocytes of Plasmodium falciparum and P. vivax respectively. Presumptive sporozoites accompanied by a stomach cyst were also observed in an insect which was fed on gametocytes of P. malari” , the parasites of quartan fever, those of sub-tertian being also present in much smaller numbers. Ross's black spores were found associated with sporozoites and cysts in several sub-tertian infected, and in one benign tertian infected, insect. These appearances were absent in laboratory-bred controls which had had no blood meals.