Fig. 1. Oocyst numbers from membrane feeds of purified Crotalus adamanteus PLA2. Open circles, the PLA2 was mixed with washed, infected chicken blood (16 % parasitemia) and fed to mosquitoes. Open triangles, the PLA2 was pretreated with p-bromophenacyl bromide (pBPB) at a final concentration of 100 µmol l^–1 and then mixed with washed, infected chicken blood (16 % parasitemia) and fed to mosquitoes. Filled circles, the PLA2 was added to an ookinete suspension in naive chicken blood and fed to mosquitoes. Filled triangles, the PLA2 was pretreated with pBPB, then added to an ookinete suspension in naive chicken blood and fed to mosquitoes. Oocyst numbers were scored 8 days after the membrane feed. Each data point represents the geometric mean of oocyst numbers from at least 20 mosquitoes expressed as percentage inhibition relative to control mosquitoes fed either with infected blood plus buffer or with infected blood plus inhibitor alone.