Photo taken on May 23, 2010

Is this a cabbage white? No. Thick grey veins on the lower side of the wings show that these are green-veined whites.

I saw many mentions that such meetings on the mud are usually visited by males. Looks like truth: most of the butterflies on the picture have only one dot on the front wings, while females of this species have two dots. The whole picture is very similar to a gathering of men in a bar. Everyone is sitting, sipping his drink, and enjoying his life :).

Translation of the Latin name gives ~“muse of rapa”: genus name Pieris derives from an epithet of Greek muses — Pierids (and that is from Pieris, a region in Ancient Macedonia where they lived).

green-veined white, mustard white Pieris napi