Labelled photographA labelled photograph of an adult butterfly illustrates most of the anatomical terms used in the text.

Abdomen The abdomen is composed of ten segments but only segments two to eight are externally visible. The abdomen contains a ventral nerve cord, digestive system, reproductive organs and a dorsal heart. The structure of the genitalia at the tip of the abdomen is important in classification.
Antennae On the top of the head there are two long sensory antennae.

Costa The front edge of the wings.

Eyes There are two compound eyes, one on either side of the head.

Head The front section/part of the body bearing two compound eyes and antennae. It is a small, round capsule composed of chitin.

Proboscis At rest the proboscis is coiled within the head. It is composed of two hollow tubes joined together, through which the insect drinks.

Thorax The thorax is made up of three segments. Each segment has a pair of legs attached. The wings are attached to second and third segments.

Wings Most butterflies and moths can readily be distinguished by the markings and shape of the wings. The wings are covered in tiny overlapping scales. The scales contain the pigment that give the wings their colour patterns. In some species e.g. the Blues and Small Copper the microscopic structure of the scales breaks up light giving the wings a metallic sheen.