Most cicada wings resist fouling and particle adhesion due to the microscopic wax structures on their wings. The wax is hydrophobic and does not wet in contact with water. Water does not spread, but forms a tight droplet that has little contact with the surface.
The wax on the wing is not smooth but rough with small tipped projections rising from the surface. Water droplets can have less contact with rough surfaces where the droplet makes minimal contact with a small number of points compared to smooth surfaces where more surface area of the droplet can make contact by flattening.
For particles such as pollen grain, the rough surface of the wing minimizes the number of points on a pollen grain that can adhere to the surface. The less area in contact between the wing surface and a particle, the lower the friction. With little friction to hold particles to the wing, water droplets, pollen grains and other contaminants are easily dislodged by wing movements that force air over the surface of the wing.