Why are ladybugs called ladybugs but they are not all ladies?

That the ladybug (Coccinellidae family) is of the same color of red as the cloak of Our Lady Mother of Jesus of Nazareth (7-2 B.C. - 30-36) and that its seven spotssymbolize Mary's seven joys and seven sorrows in life is one explanation for the name.

Specifically, the beetle in question is the seven-spotted ladybug (Coccinella septempunctata). Not all ladybugs are red in color. Not all ladybugs are limited to just seven spots.