The Holy Beetle?

We call them "ladybugs" but they're not bugs at all, they don't even qualify as insects yet they ARE beetles.  They're basically classified as a form of beetle with a hard exterior shell hiding delicate wings - a semi-exo-skeletal beetle is what I'd call them.  Where did they get such an unusual name, and what are they actually?

First they're a farmer's best pal, wisely used instead of pesticides as they munch on aphids and other pests.  They're also not hard to look at and don't sting or bite. 

The "lady" was named out of gratitude mostly from farmers centuries ago, who prayed to the Virgin Mary, the mother of the son of God, (wait, what?) yes well, it's called a glorious mystery just go with it for now; the Virgin is usually depicted in her red cloak which many believe to be the cloak of Jesus after his death, and when praying for a healthy crop farmers saw these red speckled bugs eating the aphids and were sure it was a gift from Our Lady.

Hence Ladybugs.

Don't ask me about that other thing....