238 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io9 j 



localities such as the eastern Darien Mountains, the Chiriqui high- 

 lands, the southern Chiriqui gallery forests, and the Caribbean rain 

 forests, and by a special program of collecting and rearing from larval 

 habitats we believe this number can be materially increased. This 

 phenomenal number of species of a single genus in an area as small as 

 the Republic of Panama is a result of the ecological diversity of this 

 mountainous country (Goldman, 1920; Standley, 1928; Kenoyer, 

 1929) and of its peculiar geographic position. As an isthmus between 

 two continents Panama has received species that have been stranded 

 from waves of migrations of historical faunas from north to south and 

 from south to north during geological periods of time (Chapman, 1917; 

 Schuchert, 1935; Griscom, 1935, 1940, 1950). 



For their generous cooperation and assistance in making the field 

 collections and sorting specimens in Panama, we are greatly indebted 

 to the following persons and organizations: Col. Francis P. Kintz, 

 Surgeon, and Lt. Col. Edward J. Dehne, Chief of Preventive Medi- 

 cine, U. S. Army Caribbean, and the personnel of the 25th Preventive 

 Medicine Survey Detachment; the Gorgas Memorial Laboratory, 

 especially Dr. Pedro Galindo, Dr. G. B. Fairchild, and Dr. Harold 

 Trapido; and the Inter- American Geodetic Surveys, especially Mr. 

 Elton Vickers. 



We particularly thank Mr. Gordon A. Marsh, of the University of 

 California, for making the many thousands of measurements of speci- 

 mens, a laborious task performed as a technician at the Walter Reed 

 Army Institute of Research. 



The illustrations accompanying this paper were made by Miss 

 Sakiko Asano, Mr. Kei Daishoji, Mr. Akira Shimazoe, and Miss 

 Kazuko Tsukamoto of the 406th Medical General Laboratory, U. S. 

 Army in Tokyo, Japan, under the direction of Mr. Kakuzo Yamasaki, 

 and by Mr. Thomas M. Evans, scientific illustrator of the Walter Reed 

 Army Institute of Research, Washington, D. C. The Japanese 

 artists were under the direction of Maj. Hugh L. Keegan, MSC, 

 Department of Entomology, and Col. Joe M. Blumberg, MC, Com- 

 manding Officer of the 406th Medical General Laboratory. 



For taxonomic advice and cooperation, including frequent exchange 

 of specimens and manuscript notes, we thank our co-workers on the 

 taxonomy of American Culicoides: Dr. O. P. Forattini of the Universi- 

 dade de Sao Paulo, Dr. Irving Fox of the University of Puerto Rico, 

 and Dr. Ignacio Ortiz-Cordero of the Instituto Nacional de Higiene of 

 Caracas, Venezuela. We are indebted to Dr. A. da Costa Lima of the 

 Instituto Oswaldo Cruz for the loan of type material from the Lutz 

 collection, to Dr. Irving Fox of the University of Puerto Rico for the 

 loan of numerous type specimens described by himself and Dr. W. A. 

 Hoffman, and to Mr. Paul Freeman and the trustees of the British 



