Butterflies use many means to hide themselves from predators. Sometimes, as with the neotropical metalmarks ( Riodinidae ), they simply hide under leaves, out of sight. Most other species rest in more open situations though, and conceal themselves using techniques such as camouflage, disguise, disruptive coloration or transparency.
The boundary between camouflage and disguise is hard to define, but camouflage is generally considered to describe something with a colour, pattern and texture that enables it to blend well against a natural background or substrate. Butterflies rest on many different substrates including foliage, soil, rocks and tree trunks - and various species possess colours and patterns which match each of these backgrounds.
Disguise on the other hand describes a butterfly or moth that has a similar appearance to another natural object, such as a leaf or flower. Moths often have very effective disguises - some which rest on tree trunks resemble bits of lichen, others resemble bits of broken twig. The caterpillars of many Geometrid moths look exactly like twigs, and even have small projecting false "thorns".