We work on the invasion of the mosquito midgut epithelium by the ookinete stage of malaria parasites. The ookinete develops from male and female gametes which mate and form a zygote in the bloodmeal taken from an infected person. The elongate ookinete is motile and penetrates the midgut wall to establish itself on the basement membrane of the midgut, where it rounds up and forms the oocyst. We are interested in the molecular events of parasite adhesion to and invasion of the midgut.