Carefully and properly applied, ether is still the best means of anesthetizing fruit flies. With this inexpensive device, the process is nearly foolproof, and hazards to user and flies are minimized. Ether is applied through a sidearm tube and held by absorbent cotton. Fumes are released through the funnel-shaped top, which is sized to accommodate all commonly used culture vessels—up to 4 cm (1-5/8") in diameter. Detailed, illustrated instructions are included.