Western Dappled White
Euchloe crameri
Female, Malaga, February 2007
Eastern and western dappled whites used to be classified as one species, Euchloe ausonia, but were definitively separated some ten or fifteen years ago. There is no discernible external difference between them, so in the limited areas of overlap between their ranges (just a fragment of northern Italy) the only way to distinguish them is by resorting to violence. Luckily, distribution is almost always a satisfactory test, and the insect shown here, the only one I have seen (because I so rarely go south early enough in the year) is definitely crameri. Within the range of crameri another dappled white, the Portuguese dappled white (E. tagis) does also fly, but this is easily told apart by the smoothly rounded costa of the hindwing. In crameri this edge has a sharp bend in it.
As I note on the ausonia page, many authors still follow Higgins and Riley in confusing ausonia/crameri and simplonia. This last species flies in the Alps and is also distinugished by the fact the black mark on the forewing extends to the costa and slightly along it.