Salivary glands of the female mosquito, Aedes aegypti, contain an α-glucosidase in their proximal lobes and an apyrase in the distal lobes. Following a liquid sugar meal, there is a significant reduction in the activity of the salivary glucosidase, but no significant reduction in the activity of the apyrase. Following a blood meal, both enzyme activities are significantly reduced. The rate of accumulation of both enzymes after a blood meal differs. The glucosidase activity returns to nonfed control values within 1 h of the blood meal and increases to 3 times the control values after 2 days. Salivary apyrase activity remains significantly lower than control values for up 3 h after the blood meal, reaches control values by 24 h and becomes significantly (30%) higher than control values 2 days after the blood meal. Total salivary gland protein levels remain significantly lower than control values for up to 3 h after a blood meal and return to control values at 24 h. A neuro-humoral model is postulated to explain the results.