An early 20th century gem-set gold and enamel insect watch pendant

An early 20th century gem-set gold and enamel insect watch pendant, realistically formed, the wings each set with a crescent of graduated rose-cut diamonds and a pearl on red guilloche enamel ground, push-button release opens the spring-loaded wings to reveal a small watch with white enamel dial and Roman numerals, the sides and shoulders with further black enamel decoration, the shoulders set with small diamonds and with emerald eyes, realistically engraved to the underside, inner case numbered 4904, 5.5cm