Probolomyrmex guineensis
Homology Weekly: Arolium
Foot of a Oecophylla smaragdina worker. Pretarsal claws and manubrium in red; arolium in yellow; tarsi in green (Scanning Electron Micrograph, Roberto Keller/AMNH)
This orchid-looking thing is really the foot of an ant. The large unfolded structure in between the powerful pair of claws is the adhesive organ of the foot called arolium (pl. arolia). It is basically a soft membranous bag folded into a suction cup that allows the ant to walk on vertical or upside down smooth surfaces.
