Why does the male ladybug have the name lady bug?

because it looks like a lady when she is flustered

It's original scientific name is Coccinellidae, derived from the Latin coccineus, which means scarlet. The name lady bug originated in Great Britain as "lady bird", where it became known as "Our Lady's Bird". This was because Mary (Our Lady), the Queen, in early paintings had often been shown wearing a red cloak, and the spots on the common seven spot lady bug were supposed to be symbols of her seven joys and seven sorrows. In the US, the name was adapted to lady bug because, well, it's a bug, not a bird.