Not seen a small tortoiseshell since you can't remember when? Forgotten what a peacock looks like? If you think there has been a dearth of butterflies recently you are right. Wet weather both last year and this has devastated our butterfly population. The figures for 2007 were the worst for 25 years and the knock-on effect - no butterflies, no caterpillars or chrysalises - coupled with more wet weather spell potential disaster.
Caterpillars are particular about what they eat and it is difficult to cater for them in our gardens without turning over the whole place to nettles, but we can all lobby over-fastidious local councils to leave for as long as possible their tidying up of waste places and road verges. Adult butterflies are not such fussy feeders and the exotic, non-native plants we grow are just as appetising when it comes to nectar. Buddleia davidii from China is manna. Go for the ordinary pale form because it has the best perfume - it is scent that draws in butterflies. Rather than hard prune, as we are often advised to do to make fewer bigger flowers, it is better to sever some shoots at the base while lightly pruning others and leaving a few shoots unpruned - this will stagger the flowering season.
Make sure your garden provides as much nectar as possible, especially over the next few weeks when the autumn brood of peacocks, red admirals, small tortoiseshells and commas will be on the wing. Many of these will hibernate over winter and the deeper they have drunk, the greater their reserves to survive and emerge the following spring. Plants with masses of small flowers are popular fare, whether they be arranged in umbels, spikes and racemes, or daisies (the centre of every daisy is composed of a spiral of tiny, individual flowers rich in nectar).
If you want butterflies to wing their way into your patch, plant sedums and buddleias (both easy to propagate from cuttings right now), and hemp agrimony (Eupatorium cannabinum). Include lots of daisies, especially big michaelmas daisies such as Aster novae-angliae, which is free from mildew and will take the flowering - and the nectar - on and on.