Messor is a myrmicine genus of ants with more than 100 species, all of which are harvester ants; the generic name comes from the Roman god of crops and harvest, Messor. The subterranean colonies tend to be found in open fields and near roadsides, openings are directly to the surface. Colonies can achieve huge sizes and are notable for their intricately designed granaries in which seeds are stored in dry conditions, preventing germination. The structure of Messor spp. nests is complex and the genus on the whole is one of very accomplished architects. Messor spp. are polymorphic and have a distinct caste of macrocephalic dinoergates whose role is carrying and cutting the large seeds which comprise much of the colonies' subsistence. Although they primarily feed on seeds, they occasionally eat insects and snails. Some snail shells possibly are taken into the nest because of their grain-like shape. Equipped with a tough, shining cuticle, Messor spp. are slow-moving and form long, seed-carrying runs. Colonies tend to be monogynous - founded by a single queen alone. Looking specifically at the M. arenarius species for example, like some other types of harvester ants, they emit trail pheromones as well as operating on an individual level when looking for food sources. Species Messor abdelazizi Santschi, 1921 Messor aciculatus (Smith, 1874) Messor aegyptiacus (Emery, 1878) Messor alexandri Tohme, 1981 Messor andrei (Mayr, 1886) Messor angularis Santschi, 1928 Messor antennatus Emery, 1908 Messor aphaenogasteroides Pisarski, 1967 Messor aralocaspius Ruzsky, 1902 Messor arenarius (Fabricius, 1787) Messor atanassovii Atanassov, 1982 Messor barbarus (Linnaeus, 1767) Messor beduinus Emery, 1922 Messor berbericus Bernard, 1955 Messor bernardi Cagniant, 1967 Messor bouvieri Bondroit, 1918 Messor buettikeri Collingwood, 1985 Messor caducus (Victor, 1839) Messor capensis (Mayr, 1862) Messor capitatus (Latreille, 1798) Messor carthaginensis Bernard, 1980 Messor caviceps (Forel, 1902) Messor celiae Reyes, 1985 Messor cephalotes (Emery, 1895) Messor ceresis Santschi, 1934 Messor chamberlini Wheeler, 1915 Messor clypeatus Kuznetsov-Ugamsky, 1927 Messor collingwoodi Bolton, 1982 Messor concolor Santschi, 1927 Messor decipiens Santschi, 1917 Messor dentatus Santschi, 1927 Messor denticornis Forel, 1910 Messor denticulatus Santschi, 1927 Messor diabarensis Arnol'di, 1969 Messor ebeninus Santschi, 1927 Messor excursionis Ruzsky, 1905 Messor ferreri Collingwood, 1993 Messor foreli Santschi, 1923 Messor fraternus Ruzsky, 1905 Messor galla (Mayr, 1904) Messor hebraeus Santschi, 1927 Messor hellenius Agosti & Collingwood, 1987 Messor himalayanus (Forel, 1902) Messor hispanicus Santschi, 1919 Messor ibericus Santschi, 1931 Messor incisus Stitz, 1923 Messor incorruptus Kuznetsov-Ugamsky, 1929 Messor inermis