A diminutive butterfly found only in a tiny part of Sinai, Egypt, the Sinai baton blue (Pseudophilotes sinaicus) may potentially be the world’s smallest butterfly species. The upperside of the male’s wing is a brilliant blue, while that of the female is dark brown. Both the male and female Sinai baton blue have a distinct black bar on the wing, and black fringing with a white border.

The underside of the wing of the Sinai baton blue is identical in both the male and female, with black spots on both wings and orange spots on the hindwing.

The Sinai baton blue caterpillar is usually bright green with a double row of yellow-green markings and a small black head, and its body is covered in short white hairs. The pupa is a uniform light brown, and measures around six millimetres in length.