Caddis fly larva. Light microscopy footage of a larva of the caddis fly (order Trichoptera) feeding on algae underwater, while in its cocoon. The larvae of this insect are aquatic, and develop in a silk cocoon spun from their salivary glands. The larva feeds on algae and plant and animal detritus brought to the cocoon by the water. This specimen is from the Kaw Marsh, French Guiana.