"Black butterfly."

Translation: Kupu-kupu hitam.

[christl43673]

it should either be Black butterflies=kupu-kupu hitam or Black butterfly= Kupu hitam

[WayangOrang]

No, some animals just have this 'double-names' in the singular form.

butterfly = kupu-kupu.
butterflies = kupu-kupu.

dolphin = lumba-lumba.
dolphins = lumba-lumba.

spider = laba-laba.
spiders = laba-laba.

turtle = kura-kura.
turtles = kura-kura.