Which of these is not a play by the Greek dramatist Aristophanes?

The Butterflies has nothing to do with Aristophanes.

Aristophanes (446 – c. 386 BC), son of Philippus, of the deme Kydathenaion was a comic playwright of ancient Athens. Eleven of his forty plays survive virtually complete. These, together with fragments of some of his other plays, provide the only real examples of a genre of comic drama known as Old Comedy, and are used to define it.

Also known as the Father of Comedy and the Prince of Ancient Comedy, Aristophanes has been said to recreate the life of ancient Athens more convincingly than any other author.

His eleven Surviving plays are:

The Acharnians

The Knights

The Clouds

The Wasps

Peace

The Birds

Lysistrata

Thesmophoriazusae or The Women Celebrating the Thesmophoria

The Frogs

Ecclesiazusae or The Assemblywomen

Wealth