Tentacular -um: retractile processes on the larvae of Lepidoptera.
The tongue of some Hymenoptera also is retractile within the mouth.
In Stenus this organ is retractile, and consists of two joints.
The vermiform and retractile tongue is also a most singular organ.
The claws are not retractile, or at most semi-retractile as in the Panda.
So the retractile wings were ...