Why is farfalle called "bow-tie" pasta, rather than "butterfly" pasta?

Farfalla* is the Italian word for butterfly, and the shape is exquisitely butterfly-like.  I would bet there are more English-speaking people who are familiar with butterflies than with bow ties.  The pasta dates from the 1500s in Lombardia, Italy (about a century before the Croatians invented the bow tie).

* - the "e" at the end of the pasta word is feminine plural, so it would translate as "butterflies." 

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