The multi-plumed wings of Alucita hexadactyla were subjected to esonification with simulated Rhinolophus hipposideros bat cries. The ultrasonic simulator signal had a frequency of 110 kHz, a pulse length of 1 ms, an inter-pulse interval of 3 ms and intensity of 85±4 dB. Two types of ultrasonic sensors were used: a reflection sensor and a through-beam sensor. Initially, attention was directed to this problem by observation of the slotted wing structure of the moth as well as other studies indicating that bats cannot detect thin wire. My results indicate that the multi-plumed wing reduces the intensity of the reflected bat-like ultrasonic signal. The echo reduction was due to a diffraction of the signal around the micro elements of the wing structure. The interaction mechanism of the manyplumed moth wing with the ultrasound signal was also described. The multi-plumed wing of the moth Alucita hexadactyla is biology's version of acoustic grating.