A Japanese Beetle?

The Huntington trip causes a third posting: We found a pretty large bug in the Huntington Botanical Garden's Rose Garden. About 2 cm lang, slightly greenish. Some pics are at Picasa. It was munching along in a rose flower. Big question: did we see a Japanese Beetle? These are no good in America, there is even a information page at the USDA. Their information poster talks about "six white spots" which we don't see. So it is all good?