THE NORTH AMERICAN BEETLES OF THE GENUS 



COCCINELLA 



By Th. Dobzhansky 

 California Institute 0/ Technology , Pasadena, Calif. 



The North American species of the genus Coccinella Linnaeus have 

 been studied particularly by Casey (1899) and by Leng (1903). The 

 results arrived at by these authors are, however, quite different. 

 More than twice as many forms are recognized as separate species 

 in the Casey revision as in the more recent survey of Leng. A new 

 survey of the genus is, therefore, desirable. As shown by my studies 

 (1925, 1926) on the palaearctic representatives of the genus Coccinella, 

 the structure of the genitalia is a first-class character for the deter- 

 mination of the limits of the species in this genus. Consequently, 

 the description of the genitalia is made the cornerstone of the present 

 study. 



A thorough comparison of the American species of Coccinella with 

 Eurasiatic ones seems also very desirable. The genus Coccinella 

 (hmited as defined by me, 1925) inhabits chiefly the holarctic region. 

 Only a few true Coccinella Kve outside of this region. If the holarctic 

 fauna of this genus is properly understood, the world-wide revision 

 of the genus may be easily accomplished. 



The present study is based primarily on the examination of the 

 collection of the United States National Museum, which was sent to me 

 through the kindness of Dr. E. A. Chapin. Besides this, collections 

 belonging to the following institutions and individuals were examined : 

 American Museum of Natural History, Cornell University, University 

 of Minnesota, Indiana University, Illinois State Natural History Sur- 

 vey, Cahfornia Academy of Sciences (including collections of E. C. Van 

 Dyke, F. E. Blaisdell, E. P. Van Duzee, and others), Citrus Experi- 

 ment Station, F. W. Nunenmacher, A. H. Sturtevant, F. T. Scott, and 

 P. H. Timberlake. I wish to express my gratitude to the owners and 

 to the custodians of these collections for the privilege of examining 

 their material. 



No. 2904.— Proceedings U. S. National Museum, Vol. 80, Art. 4 



68143—31 1 1 



