A gland peculiar to the ants (Formicidae) found at the posteroventral, or metathorax, angle of the metapleuron: The metapleural gland produces antibiotic substances:

The metathorax is the posterior of the three segments in the thorax (area between the head and the abdomen) of an insect, and bears the third pair of legs.

Its principal sclerites (exoskeletal plates) are the metanotum (dorsal), the metasternum (ventral or lower surface of an animal's body), and the metapleuron (lateral) on each side.