Orange Sulphur Butterfly — Gallery CanvasAn Orange Sulphur Butterfly visits a red clover flower wings open, the orange yellow coloration with black borders precise, a second clover stem curving below. This 1969 watercolour is a paired botanical and entomological study: the butterfly and its host plant rendered with equal attention, the cream coloured paper ground giving the whole composition a warm, herbarium page quality. Glen's butterfly studies occupy a distinct place in his catalogue