Bug Word of the Day: Proboscis - UF IFAS Entomology and Nematology . . . A proboscis is simply a long appendage coming out of an animal’s head, and is used to describe the nose or snout of a vertebrate, like an elephant, or the mouth of an insect, like a butterfly In insects, the proboscis is an elongated, tubular structure that is used for sucking food into the body While butterflies and moths are perhaps best