Fewest functional legs in a butterfly

Fewest functional legs in a butterfly
Who
nymphalids brush-footed butterflies)
Where
Not Applicable
When
18 November 2014
Like most true insects, adult butterflies have six thoracic legs, but in the nymphalids or brush-footed butterflies the males and (in most species) also the females have only four legs that are functional. The first pair of legs (the forelegs) is reduced in size, sometimes very greatly so, due to lacking certain limb portions, and is often pressed against the underside of the thorax so that on first sight such butterflies only seem to possess two pairs of legs instead of three. Specifically, the forelegs of the males of these butterflies lack the post-tarsus region and have fusion of the tarsal subsegments, whereas the females have forelegs reduced in size but without loss of any parts. Consequently, nymphalids are sometimes referred to as four-legged or four-footed butterflies. The forelegs are also very hairy, resembling brushes.