1900
Walter Reed, a United States Army major, was appointed president of a board "to study infectious diseases in Cuba paying particular attention to yellow fever." He concurred with Carlos Finlay in identifying mosquitoes as the agent. Ignacio Bolívar y Urrutia publishes Catálogo sinóptico de los ortópteros de la fauna ibérica. Kálmán Kertész, Mario Bezzi, Paul Stein (entomologist) and Theodor Becker published the first part of a Palaearctic Catalogue of Diptera Katalog der Paläarktischen dipteren in Budapest. 1901 William Francis de Vismes Kane A catalogue of the Lepidoptera of Ireland-the third (and first comprehensive) catalogue of the Irish macrolepidoptera. Augustus Daniel Imms General textbook of Entomology published. 10th revised edition (1977) still one of the most widely used of all insect texts. Thomas Hunt Morgan is the first to conduct genetic research with the fruit fly Drosophila melanogaster. In the Fly Room at Columbia University.
1902
Ronald Ross gained Nobel Prize for Medicine for his discovery that malaria is carried by mosquitoes. The awarding committee made special mention of the work of Giovanni Battista Grassi on the life history of the Plasmodium parasite. Charles W. Woodworth A List of the Insects of California published. Philogene Auguste Galilee Wytsman started Genera Insectorum, a multi-authored series that consisted of 219 issues, the last occurring in 1970. Otto SchmiedeknechtOpuscula Ichneumonologica. Blankenburg. William Morton Wheeler appointed curator of invertebrate zoology in the American Museum of Natural History, New York August Arthur Petry publishes Ueber die deutschen an Artemisia lebenden Arten der Gattung Bucculatrix Z. nebst Beschreibung einer neuen Art in Deutsche entomologische Zeitschrift Iris Peter Esben-Petersen publishes Bidrag til en Fortegnelse over Arktisk Norges Neuropterfauna
1905
Adolfo Lutz Beitraege zur Kenntniss der brasilianischen Tabaniden. Rev. Soc. Sci. São Paulo 1: 19–32, published Raphaël Blanchard Les moustiques. Histoire naturelle et médicale Paris, F.R. de Rudeval, published. Gabriel Höfner Die Schmetterlinge Kärntens (1905-1915)
1906
Adalbert Seitz, Gross-Schmetterlinge der Erde commenced. This vast work on Lepidoptera was published in German, English and French. It contained colour plates of all important species.
1907
William Lundbeck Diptera Danica. Genera and species of flies Hitherto found in Denmark commenced. Hamilton Herbert Druce On Neotropical Lycaenidae, with Descriptions of New Species. Proceedings of the Zoological Society of London. Henry Christopher McCook Nature's Craftsmen: Popular Studies of Ants and Other Insects. Lajos Abafi Magyarország lepkéi (butterflies of Hungary) 1907
1908
Edmund Reitter Fauna Germanica - Die Käfer des Deutschen Reiches commenced. This five volume masterwork remains in use today, almost 100 years from its inception. Leonello Picco Contributo allo studio della fauna entomologica Italiano. Elenco sistematico degli Emitteri finora raccolti nella Provincia di Roma. Arnold Spuler and Ernst Hofmann Die Schmetterlinge Europas (The Lepidoptera of Europe) was for decades a standard in the study of lepidoptera.
1909
George Henry Verrall Stratiomyidae and succeeding families of the Diptera Brachycera of Great Britain - British flies published. Carlos Chagas observed the peculiar infestation of rural houses in Brazil with Triatoma, a "kissing" bug, later demonstrating that it was the vector of Trypanosoma cruzi, and he was able to prove experimentally that it could be transmitted to marmoset monkeys that were bitten by the infected bug. His description of the new disease was to become a classic in medicine and brought him domestic and international distinction. Charles Nicolle reasoned that it was most likely lice that were the vector for epidemic typhus. He tested his theory by infecting a chimpanzee with typhus, retrieving the lice from it, and placing it on a healthy chimpanzee. Within 10 days the second chimpanzee had typhus as well. Antonio Berlese Volume I of Gli insetti loro organizzazione, sviluppo, abitudini e rapporti con l'uomo (Volume 2 1925). Arnold Pagenstecher Die geographische Verbreitung der Schmetterlinge published in Jena. Foundation of Journal of Entomology by Charles Fuller Baker, one of the first revues of economic entomology. Murinus Cornelius Piepers, Pieter Cornelius Tobias Snellen and Hans Fruhstorfer. The Rhopalocera of Java commenced. Completed 1918.