Gaillard was the son and grandson of Parisian jewelers. In 1892 he took over the directorship of the family firm, shifting the emphasis to larger-scale metalwork. His designs often incorporated inlaid metals, likely inspired by Japanese examples exhibited at Siegfried Bing's influential shop L'Art Nouveau. (Gaillard's brother, the noted furniture designer Eugène, was one of the three principal Europeans whose work was displayed there.)

Around the turn of the century, at the encouragement of his friend René Lalique, Gaillard turned back to jewelry. His designs, like Lalique's, combined unusual materials, such as horn and ivory, with more conventional precious stones, gold, and enamel. In keeping with typical avant-garde jewelry design of the time, focus was placed on the overall artistry, thus downplaying spectacular stones. This masterful pendant imitates nature with consummate accuracy, both in scale and in visual effect: it depicts two opposing moths with intertwined gold antennae. The realistic wings were carved from a single piece of horn and set with applied brown and iridescent white champlevé enamel to simulate natural markings, while each body was formed from a cut citrine.