Although the common names for this kind of tiny round beetle include “ladybird” and “ladybug”, the correct term is “lady beetle”. This is neither a bird nor a bug (“bugs” technically refers to an order of insects, of which the lady beetle is not a member).
The common name (“twice-stabbed lady beetle”) actually refers to a few related species — the one pictured is the most common (at least in Florida), Chilocorus stigma. Twice-stabbed lady beetles are predominantly black, with red or orange undersides, and two red spots on their back, one on each side. C. stigma in particular has midsized red spots and its underside is mostly black except for its abdomen, which is red or orange.
They are actually beneficial beetles in that they prey on a lot of the pests that eat our garden plants, especially scale insects. C. stigma is a very important predator of Florida red scale, which affects citrus crops.