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
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