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Hi Allan.
Looking at the canes in the wings, I think you may find two articles in next year's PCA Bulletin that shed a little light on this. One of these articles (not mine) shows a near identical butterfly, and links it to the canes in the well known antique door knobs (maker currently unknown, as you are aware). The other article (mine and a fellow collector's) links similar canes to the 'starfish' paperweights, which are probably Belgian. This is not to say that the items themselves are all from the same source, but some of the canes appear to be common. So I think the current status is 'unknown European factory'.
Is the signature cane a pulled cane, or is the shape like a '3' drawn in blue on a white plaque?
Alan