To be off, to decamp, to escape. A curious instance of argot. Canille is old French for chenille, a pupa, imago, or chrysalis. These afterwards become winged insects and take their flight. So a visitor says in France, “Il faut me sauver, ” or “Il faut decaniller. ” I must be off.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894