Fungus gnats are small (1/8 to 1/10th in.) in length, sooty gray or black, longlegged, flies. Their wings have a distinctive Y-shaped vein at the tip and their legs and antennae are long and delicate. The eggs are about 1/100 inch in length and laid in clusters. The larvae or maggots are white with black heads and are about 1/4th inch in length when full grown.