Seen from the top, the Green-veined White butterfly could easily be mistaken for a Small White; however, the characteristic greeny-grey veins on the underside of the wings are an easy means of identification. The wingspan varies between 4.5 and 5.5cm.
The females have two dark-grey spots on the upper side of each forewing, while the males have just one dark spot and grey tips on their forewings.
Apart from the Shetlands and some parts of the Scottish Highlands, this butterfly is common and widespread throughout Britain and Ireland. Elsewhere, its range extends throughout most of mainland Europe.
The eggs are laid on the undersides of larval foodplants which, as with so many white butterflies are mainly members of the family Brassicaceae, including Cuckooflower, Garlic Mustard, Wild Cabbage and Wild Radish. The Orange Tip Butterfly often uses the same plant as the Green-veined White but as the two species consume different parts of the host plant they are not in competition for food. Orange Tip caterpillars do not eat the leaves, whereas Green-veined White caterpillars eat only the leaves and do not touch the flower stems, petals or seed capsules that are the staple diet of the Orange Tips.
The eggs take about a week to hatch, depending on the weather, and then the green caterpillars take a month or thereabouts to grow full size, moulting four times in the process; then they pupate, a stage that lasts about ten days (unless overwintering) before the adult butterfly emerges.
Most years the Green-veined Whites have two or even three broods, and so they can be seen in flight from March right through until October. The butterflies in the pictures above were photographed in West Wales in early August.