Okano, K. 1948. Delle note sulle formiche giapponesi. Kontyû Kagaku 5:91-93.

Notes: Not seen. Cited in Okano (1989) and Onoyama & Terayama (1994).

Okano, K. 1989. The list of works concerning Formicidae (Hymenoptera) and it's related papers made by the Japanese during the years 1900-1949. Entomo Shirogane 2:1-15.
Okido, H. 2002. Morphological and biogeographical notes of Myrmecina flava complex (Hymenoptera, Formicidae). [Abstract.]. P. 168 in: Billen, J. P. J. 2002. XIV International Congress of IUSSI. The Golden Jubilee Proceedings. 27 July - 3 August 2002, Hokkaido University, Sapporo, Japan. Sapporo: XIV International Congress of IUSSI, 233 pp.
Okido, H.; Ogata, K.; Hosoishi, S. 2020. Taxonomic revision of the ant genus Myrmecina in Southeast Asia (Hymenoptera: Formicidae). Bulletin of the Kyushu University Museum 17:1-108. PDF
Okita, I.; Murase, K.; Sato, T.; Kato, K.; Hosoda, A.; Terayama, M.; Masuko, K. 2013. The spatial distribution of mtDNA and phylogeographic analysis of the ant Cardiocondyla kagutsuchi (Hymenoptera: Formicidae) in Japan. Sociobiology 60:129-134. PDF
Oldham, N. J.; Morgan, E. D.; Gobin, B.; Billen, J. P. J. 1994. First identification of a trail pheromone of an army ant (Aenictus species). Experientia (Basel) 50:763-765. PDF
Oldham, N. J.; Morgan, E. D.; Gobin, B.; Schoeters, E.; Billen, J. P. J. 1994. Volatile secretions of Old World army ant Aenictus rotundatus and chemotaxonomic implications of army ant Dufour gland chemistry. Journal of Chemical Ecology 20:3297-3305.
Oldham, N. J.; Morgan, E. D.; Hölldobler, B. 1994. The recruitment pheromones of Aphaenogaster (=Novomessor) cockerelli and A. (=Novomessor) albisetosus, two closely related myrmicine ants. P. 486 in: Lenoir, A.; Arnold, G.; Lepage, M. (eds.) 1994. Les insectes sociaux. 12ème congrès de l'Union Internationale pour l'Étude des Insectes Sociaux. Paris, Sorbonne, 21-27 août 1994. Paris: Université Paris Nord, xxiv + 583 pp.
Oliveira, A. M.; Feitosa, R. M. 2019. Taxonomic revision of the genus Probolomyrmex Mayr, 1901 (Hymenoptera: Formicidae: Proceratiinae) for the Neotropical Region. Zootaxa 4614:61-94. 10.11646/zootaxa.4614.1.3 PDF
Oliveira, A. M.; Powell, S.; Feitosa, R. M. 2021. A taxonomic study of the Brazilian turtle ants (Formicidae: Myrmicinae: Cephalotes). Revista Brasileira de Entomologia 65 (3):52 pp. e20210028. [online early] 10.1590/1806-9665-RBENT-2021-0028 PDF
Oliveira, M. A. de; Della Lucia, T. M. C. 1993 ("1992"). Levantamento de Formicidae de chão em áreas mineradas sob recuperação florestal de Porto Trombetas, Pará. Boletim do Museu Paraense Emílio Goeldi. Série Zoologia 8:375-384.
Oliveira, M. A. de; Della Lucia, T. M. C.; Araujo, M. S.; Cruz, A. P. da 1996 ("1995"). A fauna de formigas em povoamentos de eucalipto e mata nativa no estado do Amapá. Acta Amazonica 25:117-126. PDF
Oliveira, M. L.; Lacau, S. 2015. [New species of Pheidole, attributed to Oliveira and Lacau]. Pp. 535-536 in: Oliveira, M. L.; Mariano, C. S. F.; Costa, M. A.; Delabie, J. H. C.; Lacau, S. 2015. Pheidole protaxi sp. nov. (Hymenoptera: Formicidae), new species from tabuleiro forests of the Atlantic Forest biome. Sociobiology 62 (4):533-537. PDF
Oliveira, M. L.; Mariano, C. S. F.; Costa, M. A.; Delabie, J. H. C.; Lacau, S. 2015. Pheidole protaxi sp. nov. (Hymenoptera: Formicidae), new species from tabuleiro forests of the Atlantic Forest biome. Sociobiology 62 (4):533-537. 10.13102/sociobiology.v62i4.866 PDF
Oliveira, P. S.; Brandão, C. R. F. 1991. The ant community associated with extrafloral nectaries in the Brazilian cerrados. Pp. 198-212 in: Huxley, C. R.; Cutler, D. F. (eds.) 1991. Ant-plant interactions. Oxford: Oxford University Press, xviii + 601 pp.
Oliveira, P. S.; Klitzke, C.; Vieira, E. 1995. The ant fauna associated with the extrafloral nectaries of Ouratea hexasperma (Ochnaceae) in an area of cerrado vegetation in central Brazil. Entomologist's Monthly Magazine 131:77-82.
Oliveira, R. M.; Delabie, J. H. C.; Everhart, K. E.; Santos, A. P.; Cordeiro, C. M. 1997. Análise da importância dos fenômenos geotectônicos (falhas e dobras) na distribução da diversidade de Formicidae no sudeste da Bahia. [Abstract.]. P. 68 in: Delabie, J. H. C.; Campiolo, S.; Nascimento, I. C. do; Mariano, C. S. F. (eds.) 1997. Anais do VI International Pest Ant Symposium & XIII Encontro de Mirmecologia. Ilhéus: Universidade Estadual de Santa Cruz, 193 pp.
Oliver, I.; Beattie, A. J. 1993. A possible method for the rapid assessment of biodiversity. Conservation Biology 7:562-568.
Oliver, I.; Beattie, A. J. 1996a. Invertebrate morphospecies as surrogates for species: a case study. Conservation Biology 10:99-109.
Oliver, I.; Beattie, A. J. 1996b. Designing a cost-effective invertebrate survey: a test of methods for rapid assessment of biodiversity. Ecological Applications 6:594-607.
Olivier, A. G. 1792. Encyclopédie méthodique. Histoire naturelle. Insectes. Tome 6. (pt. 2). Paris: Panckoucke, pp. 369-704.

Notes: Publication date from Sherborn & Woodward (1906b:577). Ants pp. 469-506.

Olsen, O. W. 1934. Notes on the North American harvesting ants of the genus Pogonomyrmex Mayr. Bulletin of the Museum of Comparative Zoology 77:493-514. PDF
Olsen, T. J. 1999. Myrmica rugulosa Nylander, 1849 (Hymenoptera, Formicidae) new to Norway. Norwegian Journal of Entomology 46:88.
Olson, D. M. 1991. A comparison of the efficacy of litter sifting and pitfall traps for sampling leaf litter ants (Hymenoptera, Formicidae) in a tropical wet forest, Costa Rica. Biotropica 23:166-172.
Olson, D. M.; Ward, P. S. 1996. The ant fauna (Hymenoptera: Formicidae) of Kirindy Forest (tropical dry forest) in western Madagascar. Pp. 161-164 in: Ganzhorn, J. U.; Sorg, J.-P. (eds.) 1996. Ecology and economy of a tropical dry forest in Madagascar. Primate Report 46-1. Göttingen: German Primate Center (DPZ), 382 pp. PDF
Omelchenko, L. V. 1996. Features of the distribution of ants in the forest zone of the Western Siberian plain. [In Russian.]. Sibirskii Ekologicheskii Zhurnal 3:227-237.
Onoyama, K. 1974. The fossil ants in Mizunami amber: preliminary report (Insecta: Hymenoptera: Formicidae). [In Japanese.]. Bulletin of the Mizunami Fossil Museum 1:445-453.
Onoyama, K. 1976. A preliminary study on the ant fauna of Okinawa-Ken, with taxonomic notes (Japan; Hymenoptera: Formicidae). Pp. 121-141 in: Ikehara, S. (ed.) 1976. Ecological studies of nature conservation of the Ryukyu Islands - (II). Naha, Okinawa: University of the Ryukyus, 141 pp.
Onoyama, K. 1980a. An introduction to the ant fauna of Japan, with a check list (Hymenoptera, Formicidae). Kontyû 48:193-212. PDF
Onoyama, K. 1980b. The ant fauna of the Tsushima Island, with a comparison with the ant faunas of the adjacent areas. [Abstract.]. P. 32 in: The Organizing Committee 1980. Abstracts. XVI International Congress of Entomology, Kyoto, Japan 3-9 August, 1980. Kyoto: XVI International Congress of Entomology, 480 pp.