Wiktionary
black hairstreak
n. A brown butterfly, ''Satyrium pruni'', of the family Lycaenidae
Wikipedia
Black hairstreak
The black hairstreak (Satyrium pruni) is a butterfly in the family Lycaenidae.
Usage examples of "black hairstreak".
There were a lot of species I wanted -- the Swallowtail for instance, the Black Hairstreak and the Large Blue, rare Fritil-laries like the Heath and the Glanville.