This butterfly is so named because of its appearance on a piece of needlework, allegedly depicting a specimen taken near Bath in southern England in 1795. The name is doubly misleading, first because British specimens seem all to be of its sister species, the eastern Bath white, not in fact of this one, and secondly because even that species is an extremely rare vagrant to the British Isles and not in any way associated with the City of Bath!

In fact, owing to the historic conflation of Bath white and eastern Bath white - and their great similarity in the field - the distribution of the two species is not well known. The map above is largely taken from Leraut. He differs with some others, in showing the present species in much of Greece - where Tolman, for example, has only eastern Bath white. It is widely assumed the two cannot be separated in the field but I believe they probably can, at least in most cases. In eastern Bath white, the dark spot marked with a circle in the following pictures is largely obscured by green colouration. In the Bath white, at least some strong black is clearly visible here. This distinction holds well in Switzerland (where only eastern Bath white flies) and Spain (where only Bath white flies). It seems to work for almost all pictures of specimens in books.

Because I only see this species on my occasional visits to Spain I am much less familiar with it than with its sibling. Apart from the fact it flies earlier and later in the year, it seems to be in all respects similar in behaviour and ecology to the eastern Bath white. Like that species it passes the winter as a chrysalis.