Meet Vespa mandarinia, the world's largest hornet with body lengths of 27 to 45 mm (1" to 1 3/4"), with the queen being as large as 55 mm (about 2 1/8")!
This beast of a hornet is found in southeast part of Asian Russia, Korea, China, Cambodia, Laos, Vietnam, Nepal, India, Sri Lanka, Thailand, and Japan.
As you guessed, the giant hornet is one mean flying machine:
Additional this gigantic, voracious predator has a quarter-inch stinger (6.35mm)! People are usually not the Japanese giant hornet's prey, but those who have felt its sting describe the pain as excruciating and very painful. Masato Ono, an entomologist at Tamagawa University, near Tokyo, said it's "like a hot nail through my leg."
But they're not invincible. Their prey, the mundane honeybees, came up with an ingenious defense: baking them alive.
The Japanese giant hornet, Vespa mandarinia japonica, preys on other species of bees and wasps. When a solitary hunter finds a nest, it marks it with a secretion from its van der Vecht gland. Other hornets in the area congregate to the area, and they begin a mass attack on the colony. While they are efficient at wiping out hives of the introduced European honeybee Apis mellifera (they are killed at rates as high as 40 per minute), the native Japanese honeybee, Apis cerana japonica, has an interesting defense against the predatory hornet! The Japanese honeybees can detect the hornet's secretion, and attack incoming hornets en masse. With approximately 500 honeybees surrounding the hornet in a tight ball, the temperature within the cluster rises to 47º C (117º F), which is above the upper lethal limit range of 44-46 degrees for the hornet. This temperature is too high for the hornet, which quickly expires, but does not harm the honeybees.This temperature does not aversely affect the honeybees because their upper lethal limit is slightly higher, 48-50 degrees.
http://www.vespa-crabro.de/manda.htm - via J-Walk Blog