Proboscipedia (pb) is a protein coding gene in Drosophila melanogaster.
This hox gene participates in the development of the labial and maxillary palps and mouthparts in the Drosophila fly.
The pb gene is known to regulate the location of the antenna, maxillary palp, tarsus and proboscis identities.
Both of these are essential for determination of the proboscis, a long flexible mouthpart in many insects used for the purpose of sucking.
[1] Mutated versions of the pb gene result in prothoracic (anterior to thorax) legs from labial palps and maxillary palps that display malformation or smaller size.