Unique footage of flight and mud-puddling behaviour of a new species of clearwing moth (Lepidoptera: Sesiidae) was filmed in its habitat in Thailand. Aschistophleps argentifasciata, morphologically resembling a bee, imitates its model also in the way it flies. This behavioural mimicry, as well as mud-puddling, filmed both in real-time and slow motion (500/1000 frames per second), are shown in a supplementary video and described herein. A morphological description of the new species, including male genitalia, mimicry features, differential diagnosis from closely related species and information on the habitat, time and conditions of occurrence are provided. This is the first video of the genus Aschistophleps ever published and this species is the first country record of Aschistophleps for Thailand.