Probolomyrmex longinodus are a species of ant that nests in snail shells filled with soil. The entire genus is cryptic. Alex Wild has one of the few photos of a living ant:

Probolomyrmex
is an extremely rare proceratiine genus found in tropical regions around the world. Most species are eyeless and blind, perhaps inhabiting deep soil, but little is known about their biology. The photographs below may be the only ever taken of a living example.
(www.alexanderwild.com)
They are eyeless, and live in leaf litter, or in the previously mentioned shells.
Hard to study, hard to find, tricky to ID when you do find them. Absolute legends. Ants with secrets. #ants #rareAnt