Lang's Short-tailed Blue Butterfly - Leptotes pirithous

Phylum: Arthropoda - Class: Insecta - Order: Lepidoptera - Family: Lycaenidae

Lang's Short-tailed Blue, Leptotes pirithous


This butterfly gets its common name from the short tail on the trailing edge of each hindwing. This feature plus the distinctive mottling on the underwings make it very easy to identify Lang's Short-tailed Blue. With a wingspan of 21-29mm, the males are slightly smaller than the females, whose wingspan is 24-30mm. (With a wingspan of up to 34mm, the Long-tailed Blue is noticeably larger.) The male and female have similar underwing patterning, but the uppersides of the wings are purplish-blue in males, bluish-brown in females.


Lang's Short-tailed Blue is a common sight in Mediterranean countries, including the Iberian Peninsula, but from central France northwards it is only a very occasional sight. Apart from a single sighting in 1938 this butterfly has not been recorded in either Britain or Ireland.

Lang's Short-tailed Blue, Leptotes pirithous, Portugal

Above: this butterfly has suffered damage to its hindwings and so the tails are not evident.


The larval foodplants used by the Long-tailed Blue include various peas (Fabaceae), and it is considered a pest of Broad Bean and Pea crops in agricultural areas where it feeds first on the leaves and then on the contents of the seedpods.

In the Algarve and in southern Spain these butterflies can be seen throughout most of the year (with just a short 'Christmas holiday of a month or so!). The specimens shown here were seen in May.


This page includes pictures kindly contributed by Rob Petley-Jones.

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