The Lepidoptera are also capable of perceiving the supersonic echo-location signals of bats, which makes it possible for the Lepidoptera to hide from them in time.To a significant degree the evolution of Lepidoptera has occurred in the direction of improving flight.The placement of the varicolored scales on the wing is specific and forms complex patterns which are characteristic for each species and often for each taxonomic group.The colors and patterns of the wings have a dual biological significance.The proboscis of Lepidoptera consists of a pair of greatly extended groove-like external lobes of the lower jaws fastened into the form of a tube through which food is sucked in.Of the remaining parts of a typical insect mouth, the Lepidoptera have only a pair of labial palpi which support the coiled proboscis on both sides. In the nonfeeding species of Lepidoptera, the proboscis sometimes has completely disappeared.The olfactory organs (the so-called sensillae) are located in large numbers on the surface of the antennae.
Accordingly, the mesothoracic segment and its musculature were progressively strengthened, while the metathoric segment was weakened.
An excep tion among the Lepidoptera are the representatives of the family Micropterigidae which feed on the pollen of flowers and have kept the gnawing mouth parts with developed mandibles.
This group serves as the connecting link between the modern higher forms of Lepidoptera and their extinct predecessors, which were close to the caddis flies.
Among the European Lepidoptera, the largest is the giant silk moth, or Saturnia pyri (12–15 cm).
There are also midget forms with wings about 3 mm across, for example, the pygmy moth (Stigmellidae).
The auditory organs are located either in the area of the metathorax (owlet moths, prominents) or at the base of the abdomen (measuring worms and Pyralidae).