  Two separated levels of functionality are identified in the nanostructure
which covers the wings of the grey cicada $\textit{Cicada orni}$ (Hemiptera).
The upper level is responsible for superhydrophobic character of the wing while
the lower level enhances its anti-reflective behavior. Extensive wetting
experiments with various chemical species and optical measurements were
performed in order to assess the bi-functionality. Scanning electron microscopy
imaging was used to identify the nanostructure morphology. Numerical optical
simulations and analytical wetting models were used to prove the roles of both
levels of the nanostructure. In addition, the complex refractive index of the
chitinous material of the wing was determined from measurements.
