A few moths  have wingless females, but the insects generally have two pairs of membranous wings clothed with minute scales. The scales provide the wing colour and pattern, but they are easily detached.Insects that have been flying around for several weeks often look dull and worn as a result of losing many of their scales. Lepidopterian show little variation in structure and are easily recognised as such, but they do exhibit a remarkable range of sizes. European species have wingspans ranging from 3mm to 150mm, and some tropical species exceed 300mm.