Preliminary trails in Colombia, Ghana and Kenya have shown that a flashing fluorescent light tube in a battery-operated light trap can be very useful in trapping mosquitoes and other medically important insects. A light source that repeatedly flashes on and off also reduces the power consumption of the trap, and consequently extends the intervals between battery recharging. A description is given of a modified monks wood light trap in which the fluorescent light can either operate continuously or be made to flash on and off at different rates. A photoconductive cell is also incorporated in the circuit which allows the trap to automatically switch on at different light levels.