A proboscis // is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, the term is used to describe an elongated nose or snout.
First attested in English in 1609 from Latin proboscis, the latinisation of the Greek προβοσκίς (proboskis), which comes from πρό (pro) "forth, forward, before" + βόσκω (bosko), "to feed, to nourish". The correct Greek plural is proboscides, but in English it is more common to simply add -es, forming proboscises.
The most common usage is to refer to the tubular feeding and sucking organ of certain invertebrates such as insects (e.g., moths and butterflies), worms (including proboscis worms) and gastropod molluscs.
Lepidoptera mouth parts 
The mouth parts of Lepidoptera mainly consist of the sucking kind; this part is known as the proboscis or 'haustellum'. The proboscis consists of two tubes held together by hooks and separable for cleaning. The proboscis contains muscles for operating. Each tube is inwardly concave, thus forming a central tube up which moisture is sucked. Suction takes place due to the contraction and expansion of a sac in the head.
An abnormal facial appendage that sometimes accompanies ocular and nasal abnormalities in humans is also called a proboscis.
Notable mammals with some form of proboscis are:
- Members of the elephant family (see elephant trunk).
- Elephant shrews
- Hispaniolan Solenodon
- Leptictidium (extinct)
- Macrauchenia (extinct)
- Moeritherium (extinct)
- Palorchestes (extinct)
- Proboscis Monkey
See also 
- προβοσκίς, Henry George Liddell, Robert S, A Greek-English Lexicon, on Perseus Digital Library
- πρό, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
- βόσκω, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
- "Online Etymology Dictionary". Etymonline.com. Retrieved 2012-07-30.
- Evans, Identification of Indian Butterflies, Introduction, pp 1 to 35.
- Charles A. Triplehorn and Norman F. Johnson (2005). Borror and Delong's Introduction to the Study of Insects (7th edition). Thomson Brooks/Cole, Belmont, CA. ISBN 0-03-096835-6