The Long-tailed Blue (Leptotes boeticus) is a species of butterfly in the Lycaenidae family.
A rare vagrant to Britain, this small blue is one of the larger blues. Females have a blue colouring to their wings, but these are mostly dark. Males are violet-blue. Both sexes have two black dots on the lowerer half of the hindwing (the female has a white border to it), and a "tail" which can be found between the two dots. The underside is a light brown.