Oldroyd H., 1968: New Therevidae from Argentina. 9 pp. 

 Oldroyd H., 1972: Asilidae (Diptera) d’Espagne (Pyrénées et Montes Universales). 4 pp. [M42] 

 Oldroyd H., Emden F., Jones C. G., Sabrosky C. W., Richards O. W., Munro H. K., 1957: British Museum (Natural History) Ruwenzori Expedition 1934-1935. Index to Vol. II 1939-1957 (Diptera). 13 pp. 

 Olejníček J., (ed.), 1988: Medical and veterinary dipterology. Proceedings of the international conference. November 30 – December 4, 1987, České Budějovice, Czechoslovakia. 305 pp.  Discount 50%!

 Olejníček J., (ed.), 1988: Medical and veterinary dipterology. Proceedings of the international conference. November 30 – December 4, 1987, České Budějovice, Czechoslovakia. 305 pp. 

 Olejníček J., 1973: Příspěvek k poznání druhů čeledi Dolichopodidae (Diptera) v Čechách. 5 pp. 

 Olejníček J., 1982: Příspěvek k poznání druhů rodu Medetera (Diptera, Dolichopodidae) v ČSSR. 3 pp. [ZCS 18041] [M40] 

 Olejníček J., 1986: Blackflies in the prospective Hněvkovice Dam Lake Region. 4 pp. (in Czech). 

 Olejníček J., 1988: Příspěvek k poznání fauny čeledi Dolichopodidae (Diptera) východočeského kraje. A contribution to the knowledge of the family Dolichopodidae (Diptera) in east Bohemian region. 6 pp. (in Czech). Reginaehradecensis S. A. Scientiae Naturales 21: 39-44.

 Olejníček J., Barták M., 1996: Faunistic records from the Czech Republic – 41 Diptera: Dolichopodidae. 2 pp. [M50] Klapalekiana 32(1-2): 129-130.

 Olejníček J., Barták M., 1997: Some faunistically interesting Dolichopodidae (Diptera) from Europe. 3 pp. 

 Olejníček J., Kozánek M., 1997: Systenus slovaki sp. nov. (Diptera, Dolichopodidae) from Korea. 3 pp. Entomological Problems 28(2): 127-129.

 Olejníček J., Mocek B., 1996: Faunistic records from the Czech Republic – 47. Diptera: Dolichpodidae. 1 pp. [M54] Klapalekiana 32(3-4): 200.

 Olejníček J., Rozkošný R., 1978: Some species of Dolichopodidae (Diptera) new to the fauna of Czechoslovakia. 9 pp. 

 Olivares G. E., 1958: Caracteres que se utilizan en la sistematica del orden Diptera. 13 pp. 

 Oliveira S. J. de, 2000: A new, non-marine species of the genus Thalassomya Schiner, 1856 (Insecta, Diptera, Chironomidae, Telmatogetoninae). 4 pp. Spixiana 23(2): 117-120.

 Oliveira S. S., Souza Amorim de D., 2012: Two new species of Stenophragma Skuse from Western Australia (Diptera, Mycetophilidae, Sciophilinae). 10 pp. Records of the Australian Museum 64(2-3): 149-158.

 Oliveira-Costa J., Mello-Patiu de C. A., Lopes S. M., 2001: A influencia de diferentes fatores na freqüencia de dípteros muscóides em cadáveres humanos no Rio de Janeiro. 10 pp. (in Portuguese). Boletim do Museu Nacional (N.S.) Geologia 470: 1-10.

 Oliver D. R., 1962: A review of the subfamily Orthocladiinae (Chironomidae, Diptera) of Bear Island. 19 pp. 

 Oliver D. R., 1970: Designation and description of lectotypes of the six greenland Orthocladiinae (Dipt. Chironomidae) described by Lundbeck in 1898. 7 pp. 

 Olsufiev N. G., 1969: To the taxonomy and distribution of Tabanidae (Diptera) of the Palaearctic region. 7 pp. Acta entomologica Bohemoslovaca 66: 115-121.

 Olsufiev N. G., Leclercq M., 1971: Some problems of the nomenclature of palaearctic Tabanidae (Diptera). 2 pp. 

 Olsufiev N. G., Moucha J., Chvála M., 1964: Chrysozona scutellata sp. n. aus Mitteleuropa (Diptera, Tabanidae). 3 pp. [DIP 2493] Acta Societatis entomologicae Cechosloveniae 61: 284-286.

 Olsufiev N. G., Moucha J., Chvála M., 1967: Zur taxonomie und Verbreitung der europäischen und kleiasiatischen Arten der Tabanus bovinus – Gruppe (Diptera, Tabanidae). 11 pp. Acta entomologica Bohemoslovaca 64: 303-313.

 Olszak R., 1979: Occurrence of gall midges (Diptera, Cecidomyiidae) in aphid colonies on apple trees. 11 pp. (in Polish). [DIP 2495] Polskie Pismo Entomologiczne 49: 185-195.

 Omelková M., Ježek J., 2012: A new species of the genus Trichomyia (Diptera: Psychodidae) and new faunistic data on non-phlebotomine moth flies from the Podyjí NP and its surroundings (Czech Republic). 29 pp. Acta Entomologica Musei Nationalis Pragae 52(2): 505-533.

 Omoloye A. A., 2010: Effects of genotype variation in the cultivated rice species on the biology and galling characteristics of the African rice gall midge, Orseolia oryzivora (Diptera: Cecidomyiidae). 8 pp. Entomological Science 13(3): 320-327.

 Omoloye A. A., Vidal S., 2007: Abundance of 24-methylenecholesterol in traditional African rice as an indicator of resistance to the African rice gall midge, Orseolia oryzivora Harris & Gagné. 9 pp. Entomological Science 10(3): 249-257.

 Ondráček J., Rupeš V., Žďárek J., Lineva V. A., 1976: Lethal effects of microwaves on strains of Musca domestica, having different resistance to insecticides. 3 pp. Acta entomologica Bohemoslovaca 73: 283-285.

 Ono H., 1978: Description of a new Odagmia-species, O. nishijimai n. sp. (Diptera, Simuliidae) from Japan. 9 pp. Kontyu, Tokyo 46(1): 43-51.

 Ono H., 1980: Some new species of black flies (Diptera, Simullidae) from Hokkaido, Japan. 29 pp. Kontyu, Tokyo 48(3): 333-361.

 Onsoy C., Altunsoy F. A., Akay F. H., 2014: A new record for the Turkish house fly fauna: Mesembrina meridiana (L. 1758) (Diptera: Muscidae). 5 pp. Journal of the Entomological Research Society 16(2): 23-27.

 Onsoy C., Altunsoy F. A., Akay F. H., 2014: A new record for the Turkish house fly fauna: Mesembrina meridiana (L. 1758) (Diptera: Muscidae). 5 pp. Journal of the Entomological Research Society 16(2): 23-27.

 Oosterbroek P., 1994: Notes on western Palaearctic species of the Tipula (Yamatotipula) lateralis group, with the description of a new species from Turkey (Diptera: Tipulidae). 7 pp. [DIP 6559] European Journal of Entomology 91(4): 429-435.

 Oppenoorth F. J., Dresden D., 1953: Selection of a bhc-resistant strain of Drosophila melanogaster Mg. 6 pp. 

 Orendt C., 2000: Chironomids of small Alpine water bodies (springs, spring brooks, pools, small lakes) of the northern Calcareous Alps (Insecta, Diptera, Chironomidae). 8 pp. Spixiana 23(2): 121-128.

 Ormerod E. A., 1886: Cecidomyia destructor, Say, in Great Britain. 6 pp. 

 Országh I., 1969: Contribution to the occurrence of the species of genus Culicoides Latreille, 1809 (Diptera, Ceratopogonidae) on the territory of Czechoslovakia. 6 pp. 

 Országh I., 1969: New species of genus Culicoides Latreille, 1809 (Diptera, Ceratopogonidae). 9 pp. Annotationes Zoologicae et Botanicae 59: 1-9.

 Országh I., 1974: Five species of Culicoides latreille, 1809 (Diptera, Ceratopogonidae) new for Czechoslovakia. 7 pp. 

 Országh I., 1992: Pakomáriky rodu Culicoides (Diptera, Ceratopogonidae) okolia československého úseku Dunaja. 13 pp. [DIP 2502] Entomological Problems 22: 1-13.

 Országh I., Bakošová A., 1982: Species of the genus Forcipomyia (Diptera, Ceratopogonidae) occurring in Czechoslovakia. 5 pp. 

 Országh I., Mašán P., 1989: Sezónna dynamika populácií pakomárika Culicoides obsoletus (Diptera, Ceratopogonidae) na Slovensku. 10 pp. Entomological Problems 19: 59-68.

 Országh I., Minář J., 1986: Biting midges of the genus Culicoides (Diptera, Ceratopogonidae) of South-Western Bohemia. 6 pp. (in Slovakian). 

 Országh I., Okáli I., 1978: The history of dipterology in Slovakia in the 18th and 19th century (Abstract). 2 pp. (in Slovakian). 

 Országh I., Trpiš M., 1970: A contribution to the knowledge of little known species of genus Culicoides Latreille (Diptera, Ceratopogonidae) from Czechoslovakia. 11 pp. 

 Ortiz I., 1951: Estudios sobre Culicoides (Diptera, Ceratopogonidae). VII. – Culicoides dominicii n. sp. y Clave para el reconocimiento de las especies venezolanas. 12 pp. 

 Ortiz I., 1954: Description de dos nuevas especies del genero Phlebotomus Rondani (Diptera, Psychodidae) de Venezuela. 20 pp. 

 Ortiz I., 1965: Contribucion al estudio de los flebotomos americanos del grupo Cayennensis con la descripcion de una nueva especie: Phlebotomus yencanensis n. sp. (Diptera: Psychodidae). 7 pp. 

 Ortiz I., 1965: Contribucion al estudio de los flebotomos americanos del grupo Sanguinarius con la descripcion de una nueva especie: Phlebotomus scorzai n. sp. (Diptera: Psychodidae). 15 pp.