High Quality Content by WIKIPEDIA articles! The external morphology of Lepidoptera is the physiological structure of the bodies of insects belonging to the order Lepidoptera, also known as butterflies and moths. Lepidoptera are distinguished from other orders principally by the presence of scales on the external parts of the body and appendages, especially the wings. Butterflies and moths vary in size from microlepidoptera only a few millimetres long, to conspicuous animals with a wingspan of many inches, such as the Monarch butterfly and Atlas moth. Comprising over 160,000 described species, the Lepidoptera show many variations of the basic body structure which have evolved to gain advantages in lifestyle and distribution.