Acknowledgments 



The ground work for this review was laid by a study 

 of the collections at the United States National Mu- 

 seum, the American Museum of Natural History, and 

 the Museum of Comparative Zoology of Harvard Uni- 

 versity. Especially important is the collection of the 

 U.S. National Museum, containing as it does extensive 

 material from North and South America and the Baker 

 collection from the South Pacific, besides the recently 

 acquired Bromley collection. 



The extensive collections at the British Museum 

 (Natural History), the Hermann collection in the 

 Staatssammlichen Museum in Munich and the larger 

 collections in Australia have also been studied, as well 

 as material loaned by dipterists in the United States 

 and abroad. 



The National Science Foundation gave a grant which 

 made possible the study of museum collections in the 

 United States, England, Europe and Australia. The 

 University of Mississippi provided a temporary Re- 

 search Professorship, permitting travel time. I wish 

 especially to thank the Honorable Walter Sillers of 

 Rosedale, Mississippi, and the Honorable R. D. Morrow, 

 Sr., of Brandon, Mississippi, for their willingness to 

 encourage state support for this monograph. 



I wish to express my deep appreciation to the Na- 

 tional Science Foundation for support of this project, 

 and for the helpfulness of the officials of that 

 organization. 



To the many persons who have assisted in this study, 

 especially to officials of the Smithsonian Institution and 

 its U.S. National Museum, I acknowledge with grati- 

 tude my indebtedness. I wish to express my apprecia- 

 tion to members of the Department of Agriculture 

 staff at the National Museum, particularly to Dr. Willis 

 Wirth for his deep interest in the project and to Mr. 

 Curtis Sabrosky, who has been most helpful in advice 

 and guidance concerning problems of nomenclature. 

 For encouragement during preparation of the manu- 

 script I shall always have a deep feeling of gratitude 

 toward Dr. J. F. Gates Clarke, curator of insects at the 

 National Museum. I should also like to thank the Mu- 

 seum editor, Mr. John S. Lea who deserves especial 

 mention for his patience and skill in getting the manu- 

 script and drawings into print. 



Especially I express my appreciation to Dr. Frank 

 Carpenter, Dr. P. J. Darlington and Dr. J. Bequaert 

 of the Museum of Comparative Zoology; to Dr. Mont 

 Cazier and Dr. Howard Outran at the American Mu- 

 seum of Natural History; to Dr. Edward Ross, Cali- 

 fornia Academy of Science; to Dr. P. D. Hurd, Jr., 

 and Mr. A. T. McClay of the University of California ; 

 to Mr. Joseph Wilcox of the United States Bureau of 

 Entomology, Whittier, California. I wish also to 

 thank Dr. Charles H. Martin of Oregon State College, 

 Mr. Henry Dietrich of Cornell University, Mr. George 

 Steyskal of Grosse He, Michigan and Dr. George 

 Byers of the University of Kansas. The late Dr. 

 Stanley Bromley was generous in his assistance. 



I owe a debt of gratitude to the authorities of the 

 British Museum (Natural History), Mr. N. Riley, Dr. 

 W. E. China, and Mr. H. Oldroyd, and their staff; to 

 the late Dr. Fritz van Emden of the Commonwealth 

 Institute; to Dr. George Varley and Mr. B. M. Hobby 

 of the Hope Museum, Oxford University ; to Dr. Rich- 

 ard Frey of the University Museum, Helsingf ors ; to Dr. 

 Willi Hennig of Deutsches Entomologisches Institut; 

 to the late Prof. Hassan C. Efflatoun Bey ; to Dr. A. J. 

 Nicholson and Dr. D. F. Waterhouse of the Australian 

 Commonwealth Scientific and Industrial Research Or- 

 ganization of Australia and those of his efficient staff 

 named below ; to Dr. W. Forster and Dr. F. Kiihlhorn 

 of the Staatssammlichen Museum in Munich ; to Prof. 

 J. Timon-David, University of Marseilles; to Sr. 

 Messias Carrera of Sao Paulo ; Mr. B. R. Stuckenberg, 

 Natal Museum, Union of South Africa. 



There were many in Australia who were generous in 

 their help, and to them I extend thanks : Mr. R. T. M. 

 Pescott and Mr. Alexander Burns of the National Mu- 

 seum; to Dr. and Mrs. (Dr.) I. M. Mackerras of the 

 Queensland Institute of Medical Research; to Prof. 

 F. A. Perkins and Dr. Elizabeth N. Marks of the Uni- 

 versity of Queensland; to Mr. George Mack of the 

 Queensland Museum; to Mr. A. Musgrave of the 

 Australian Museum ; to Dr. P. D. F. Murray, Dr. A. R. 

 Woodhill, and Mr. J. R. Henry of the University of 

 Sydney; to Mr. D. J. Lee, Public Health and Tropical 

 Medicine, University of Sydney ; to Mr. H. Womersley, 

 South Australian Musuem; to Mr. Harry Lower of 



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IX 



