Real Dictionary

Japanese beetle in American English
a shiny, green-and-brown scarab beetle (Popillia japonica), orig. from Japan, which eats leaves, fruits, grasses, and roses and is damaging to crops
noun: a small beetle, Popillia japonica, of the scarab family, introduced into the eastern U.S. from Japan, the adult of which feeds on the foliage of fruit and other trees, and the larva of which feeds on plant roots

Japanese beetle in British English
noun: a scarabaeid beetle, Popillia japonica, that eats the leaves and fruits of various plants: accidentally introduced into the US from Japan