うすばかげろうじゃなかったです
薄羽蜉蝣じゃなかったです
usubakagerōjanakattadesu

Noun
Desu Copula

The polite, past negative form of うすばかげろう

1. Wasn't a mayfly.; Wasn't light/thin like a mayfly.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana