In the UK the Vespa Crabro is called a hornet where in America, they call the European hornets. The hornets sting is very painful, more so than a normal wasp but due to the fact that it can inject more venom than a wasp as it is larger. With the venom being much the same as a wasps, if you are allergic to a wasp sting then there is an almost certain chance you will be allergic to a hornets sting. Much like bees, a hornet will only sting if they feel threatened, you move to quickly or you get in there way. The hornets actual sting is like a wasp where it is smooth allowing it to enter and withdraw without it breaking of though it can happen. Being able to do this allows the hornet to sting multiple times. The stinger is connected to a sac filled with around 50mg of venom. With each sting, between 10 and 15mg of venom can be injected allowing for around 3 to 5 stings before the venom sac is empty.