Nova acta Academiae Caesareae Leopoldino-Carolinae Germanicae Naturae Curiosorum - Kaiserlich Leopoldinisch-Carolinische Deutsche Akademie der Naturforscher (E. Blochmanni et Filii, 1894)

Nova acta Regiae Societatis Scientiarum Upsaliensis - Kungl. Vetenskaps-societeten i Uppsala. (Almqvist & Wiksells, 1821)

Novæ species insectorum. Centuria I - Forster, Johann Reinhold, 1729 -1798 (T. Davies, B. White, 1771)

Nuovi annali delle scienze naturali (1852)

Österreichs allgemeine baumzucht, : oder Abbildungen in- und ausländischer Bäume und Sträuche, deren Anpflanzung in Österreich möglich und nützlich ist - Schmidt, Franz, 1751 -1835 (Ignaz Albertischen Buchdruck, 1800)

Observations et Mémoires sur la Physique, sur l'Histoire Naturelle et sur les Arts et Métiers, etc (1785)

Observations et Mémoires sur la Physique, sur l'Histoire Naturelle et sur les Arts et Métiers, etc (1789)

Observations in natural history : with an introduction on habits of observing, as connected with the study of that science ; also a calendar of periodic phenomena in natural history ; with remarks on the importance of such registers - Jenyns, Leonard, 1800 -1893 (John van Voorst, 1846)

Observations on the bionomics of the bee Andrena (Tylandrena) erythrogaster Ashmead (Hymenoptera: Andrenidae) with notes on A. (Micrandrena) personata Robertson and A. (Holandrena c. cressonii Robertson - Illinois. Natural History Survey Division (Illinois Natural History Survey, 1988)

Observations on the embryology of insects and arachnids - Bruce, Adam Todd, 1860 -1887 (Johns Hopkins University, 1887)

Observations on the embryology of insects and arachnids - Bruce, Adam Todd, 1860 -1887 (Publication agency of John Hopkins University, 1887)

Occasional papers of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1869)

Occasional papers of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1875)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 1901)

Official catalogue of exhibitors. Universal exposition. St. Louis, U.S.A. 1904. : Division of exhibits. Department A. Education [to H. Agriculture; J. Horticulture to P. Physical Culture; R. Livestock.] (For the Committee on press and publicity by the official catalogue company inc, 1904)

Official lists and indexes of names and works in zoology Supplement 1986-2000 - International Commission on Zoological Nomenclature (International Trust for Zoological Nomenclature, c/o Natural History Museum, 2001)

Official lists and indexes of names and works in zoology - International Commission on Zoological Nomenclature (ICZN, 1987)

Okens Lehrbuch der Naturgeschichte - Oken, Lorenz, 1779 -1851 (Bei Carl Heinrich Reclam, 1815)

On animal and vegetable parasites of the human body a manual of their natural history, diagnosis, and treatment - Lankester, Edwin, 1814 -1874 (Printed for the Sydenham Society, 1857)

On animal and vegetable parasites of the human body, a manual of their natural history, diagnosis, and treatment - Küchenmeister, Friedrich, 1821 -1890 (Printed for the Sydenham Society, 1857)

On the Coleoptera known to occur in Indiana - Blatchley, W. S. (Willis Stanley), 1859 -1940 (W.B. Burford, contractor for state printing, 1910)

On the habits and instincts of animals - Swainson, William, 1789 -1855 (Printed for Longman, Orme, Brown, Green, & Longmans, 1840)

On the history and natural arrangement of insects - Shuckard, William Edward, 1802 -1868 (Printed for Longman, Brown, Green & Longman's Paternoster Row, 1840)

On the history and natural arrangement of insects - Shuckard, William Edward, 1802 -1868 (Printed for Longman, Orme, Brown, Green, & Longmans [etc.], 1840)

On the natural history of the Gulf of St. Lawrence and the distribution of the Mollusca of Eastern Canada - Bell, Robert, 1841 -1917 (s.n.], 1859)

On the origin & metamorphosis of insects - Lubbock, John, Sir, 1834 -1913 (Macmillan, 1890)

On the origin and metamorphoses of insects - Lubbock, John, Sir, 1834 -1913 (Macmillan, 1874)

On the origin and metamorphoses of insects - Lubbock, John, Sir, 1834 -1913 (Macmillan, 1890)

On the origin and metamorphoses of insects - Lubbock, John, Sir, 1834 -1913 (Macmillan and co, 1874)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1956)

Opuscules entomologiques - Mulsant, Martial Étienne, 1797 -1880 (L. Maison, 1858)

Order Coleoptera - Smith, John Bernhard, 1858 -1912 (New Jersey State Museum, 1909)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1891)

Ornitologia della Papuasia e delle Molucche - Salvadori, Tommaso, 1835 -1923 (G.B. Paravia, 1889)

Osservazioni naturali intorno alle cavallette nocive della Campagna Romana / [da Luigi Metaxa e Sebastiano Rolle] - Rolle, Sebastiano, (Vincenzo Poggioli, 1825)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1903)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1906)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1913)

Our common insects. A popular account of the insects of our fields, forests, gardens and houses - Packard, A. S. (Alpheus Spring), 1839 -1905 (Naturalists' Agency, 1873)

Our common insects A popular account of the insects of our fields, forests, gardens, and houses - Packard, A. S. (Alpheus Spring), 1839 -1905 (Estes and Lauriat, 1873)

Our living world; an artistic edition of the Rev. J. G. Wood's Natural history of animate creation - Wood, J. G. (John George), 1827 -1889 (S. Hess, 1885)

Outlines of comparative anatomy and medical zoology - Allen, Harrison, 1841 -1897 (Lippincott, 1874)