Green-veined White Pieris napi
This butterfly along with the other whites usually flits quickly around the garden flowers rarely settling for long although plenty visit the garden each year. It quite liked the lavender, settling for as long as three second sometimes.
This underside view shows how similar it is at first glance to a Wood White with which it is occasionally confused.
It has a variety of food plants in the wild such as Sinapis arvensis (Charlock) and various Cardamine ssp but I remember many caterpillars on our Nasturtiums in my parents' garden.
LHS: Garden, Cheshire 30th July 2008 RHS: Field near Alvanley, Cheshire 26th July 2008
Added on 22nd Oct 04, amended on Jan 31st 05, updated 27th June & 30th July & Nov 6th 08, Updated 5th June 2010