The scarce large blue (Phengaris teleius) is a species of butterfly in the family Lycaenidae. It is found in Austria, Slovenia, Croatia, the Czech Republic, France, Georgia, Germany, Hungary, Italy, Japan, Kazakhstan, Mongolia, the Netherlands, Poland, Romania, Russia, northern Serbia, Spain, Switzerland, and Ukraine and East across the Palearctic to Japan. The species was first described by Johann Andreas Benignus Bergsträsser in 1779.
The larva of this species first feeds on Sanguisorba officinalis (great burnet), then moves onto ant nests and is a predator of the ant brood. Myrmica rubra and Myrmica scabrinodis have been reported as frequent host ant species. A recent microhabitat preference study indicates that grazing is necessary for maintaining the present distribution and abundance of these butterflies.
