thorax, M. regularis is noticeably smaller than M. forficata. The mandibles of M. regularis are much narrower, the posterior corners of the head are more round and the petiolar peduncle is longer. The mandibles appear to be deep red, and some areas, such as the gastric segments, are golden brown. Distribution and habitat Myrmecia regularis is found in the south-western coastal regions of Australia. Nests have been recorded in the towns of Albany, Denmark, Nornalup, Manjimup, Pemberton and around the Margaret River in south Western Australia, Kangaroo Island in South Australia and Portland in Victoria. The ant prefers to inhabit a variety of rural environments, including woodland, open forests, dry marri forests, tree heath and granite mountains. In particular, it is a dominant species in Eucalyptus woodland, especially when E. diversicolor, E. gomphocephala and E. marginata trees are present. M. regularis colonies do not form mounds, but rather nest in damp, black soil or under large stones and logs with 100 to 200 workers present. These colonies are usually found at altitudes of between above sea level. Excavated incipient nests (young colonies beginning to develop) show small chambers wide, where logs and stones form the roof of the cell. The ground is flat with walls continuous on all sides; the outer walls tend to be thin, as they are situated near the edges of a log or stone. Most nests have a gallery which descends further into the ground, usually around and forms a small and more irregular chamber. Behaviour and ecology Myrmecia regularis is a highly aggressive ant that will pursue any intruder to a distance of 1.8–2.7 metres (2–3 yards) if their nests are disturbed. Their stings are very painful and particularly powerful. In some cases, human victims of M. regularis bites have displayed an allergy to the venom. In a 2011 study which investigated the causes of ant sting anaphylaxis in Australia, 265 of the 376 human participants reacted to the sting of several Myrmecia species. Of these, nine serum samples taken from patients were IgE positive to the venom of M. regularis. These ants are both diurnal and nocturnal, foraging on the trunks of Eucalyptus trees to feed on sap and nectar, or capturing small insects (such as caterpillars and ants in the genus Camponotus or subgenus Orthocrema). The larvae are carnivorous and exclusively feed on insects, either consuming small portions of the insect or all