As mentioned previously, Butterflies and Moths share the same Order (Lepidoptera). Describing the differences is not straight foreward.
Despite the difficulty in separation, the following families within Lepidoptera are considered to be butterflies.
Papilionidae - Swallowtails and Birdwings which are not seen in the UK.
Pieridae - White or Yellow white butterflies.
Lycaenidae - Blues and coppers.
Riodinidae - Metalmark butterflies. Only one member of this family can be seen in the UK - Duke of Burgundy Fritillary (Hamearis lucina)
Nymphalidae - Brush foot butterflies.
Satyridae - Mainly Brown butterflies.
Hesperiidae - Skippers.
Note 1: Danainae (or Danaids) were originally a separate family (Danaidae) but are now grouped with Nymphalidae.
Note 2: Only butterflies that I have photographed (from 2008) are included below. This section will expand as I see and photograph more
This is a large family with some common and very easily recognised members found in the UK. Some (e.g. Large White, Small White and Clouded Yellow) are Migrants.
The pupae are attached to a vertical surface, such as the food plant itself, supported by a silken belt.
A large family of generally small butterflies. The males are brilliantly coloured and usually differ greatly in colour and markings from the females.
Larvae are small and squat with concealed legs giving them the appearance of a woodlouse.
Pupae are attached upright on the food plant or attached to litter around the plant by a few strands of silk.
A large family of colourful butterflies, some of which are instantly recognisable and are seen in the garden. The colour is usually only on the top wing surface, The undersides are generally drab but with distinctive patterns. The front legs are much reduced and not used for walking.
Larvae are generally spiny.
The pupae often have bright metallic spots and are suspended from the food plant.
A large family of mainly brown butterflies with 'eye' spots on the wings. The purpose of these is to lure birds away from the vulnerable head to the less sensitive wing margins.
Another key in identifying butterflies of this family is the distinctively swollen veins at the base of the wing. The front legs are much smaller and brush like.
Larvae feed on grasses and are green or brown. They have two prongs at the rear.
Pupae either hang upside down or lie in a flimsy cocoon in the turf.
An ancient butterfly family which differs greatly from other families. Its head is large and the thorax is equally large. Antennae are widely separated at the base. Flight is fast and darting.
Larvae feed and pupate in a silken shelter on the food plant.