repeatedly without any harm to themselves. The retractable sting is located in their abdomen, attached to a single venom gland connected by the venom sac, which is where the venom is accumulated. Exocrine glands are known in some species, which produce the venom compounds later used to inject into their victims. Examined workers of larger species have long and very potent stingers, with some stings measuring . Interaction with humans Myrmecia is one of the best-known genera of ants. Myrmecia ants usually display defensive behaviour only around their nests, and are more timid while foraging. However, most species are extremely aggressive towards intruders; a few, such as M. tarsata, are timid, and the workers retreat into their nest instead of pursuing the intruder. If a nest is disturbed, a large force of workers rapidly swarms out of their nest to attack and kill the intruder. Some species, particularly those of the M. nigrocincta and M. pilosula species groups, are capable of jumping several inches when they are agitated after their nest has been disturbed; jumper ants propel their jumps by a sudden extension of their middle and hind legs. M. pyriformis is considered the most dangerous ant in the world by the Guinness World Records. M. inquilina is the only species of this genus that is considered vulnerable by the IUCN, although the conservation status needs updating. Fatalities associated with Myrmecia stings are well known, and have been attested to by multiple sources. In 1931 two adults and an infant girl from New South Wales died from ant stings, possibly from M. pilosula or M. pyriformis. Another fatality was reported in 1963 in Tasmania. Between 1980 and 2000, there were six recorded deaths, five in Tasmania and one in New South Wales. Four of these deaths were due to M. pilosula, while the remaining two died from a M. pyriformis sting. Half of the victims had known ant-sting allergies, but only one of the victims was carrying adrenaline before being stung. Most victims died within 20 minutes of being stung, but one of the victims died in just five minutes from a M. pyriformis sting. No death has been officially recorded since 2003, but M. pilosula may have been responsible for the death of a man from Bunbury in 2011. Prior to the establishment of a desensitisation program, Myrmecia stings caused one fatality every four years. Venom Each Myrmecia species