What is the difference between a lady bug and a Japanese beetle?

Color: Native ladybug is RED, Asian lady beetle ranges from orange to tan to yellow (or even black).

"Despite the wide variation in background color and number of spots, [Asian Lady Beetles] all share a distinguishing mark on their pronotum...that small section that separates the head area from the abdomen (where the wing covers start). There is a mark on the pronotum that looks like a "W" or "M" depending upon whether you are looking at it from the front or rear. All multi-colored Asian lady beetles have this mark that domestic ladybugs lack."

Both are different from the Japanese Beetle, which is a metallic green-brown, and slightly larger than either Lady. It is considered a pest, and devours many plants. It can strip the leaves off a plant (trees, crops, and ornamentals such as roses, etc.) resulting in considerable damage to the plant, even killing them. You can purchase Japanese Beetle Traps which are baited with pheromones and are very effective in drawing them. In infested areas, it is not unusual for each trap to catch a quart of the insects a day in the height of the season.