11)8 Journal New York Entomological Society. [Voi. ix. 



and this great valley region, which is enclosed at both the northern and southern ends 

 by transverse ranges. Through breaks in the Coast Range, flow two large rivers into 

 San Francisco Bay. 



Chronologically, the Sierras are older than the Rocky Mountains, California ex- 

 isting when the Great Basin region was a vast inland sea. It was also much less 

 subjected to glacial influences, thus permitting the survival of much of the ancient 

 fauna. Contiguity to the ocean of a land of such great variation in topography 

 naturally causes much diversity of climate. Four distinct climatic areas are recognized, 

 viz.: the coast, interior valley, Sierra or higher mountain, and desert or semi -desert. 

 The climate of the coast is tempered by the Japan current, and is cool and even ; that 

 of the valley (600 miles in length) is warm in summer, but without rain, and the re- 

 verse in winter ; that of the Sierra mild and dry in summer with little rain, but 

 severe in winter ; and that of the desert intensely hot and dry in summer, and dry and 

 mild or cold in winter, varying with the altitude. We find Dr. Merriam's theory that 

 there are traces of two distinct insect faunas, one derived from the Boreal and the 

 other from the Sonoran regions corroborated by the fact that among the coleoptera 

 identical or affiliated forms and species indigenous to the Boreal region occur more 

 frequently as we go northward with like result as regards the Sonoran as we go south- 

 ward, representatives of both faunas overlapping. Contributions from the Alaskan 

 Maritime region also prevail along the coast belt, certain species even occurring as 

 far south as San Francisco, but in no case east of the Coast Range. In the northern 

 elevated section between and including the Coast Range and the Sierras are found 

 representatives of the so-called Canadian fauna and these often follow the ranges even 

 to Lower California. It is probable that among the highest Sierras could be found 

 examples or affiliated forms of the Hudsonian, timber line and Arctic faunas. The 

 fauna of that portion of the Colorado desert within the State lying east of the San 

 Bernardino Mountains and including the counties of San Diego, San Bernardino and 

 the southern part of Inyo is distinctly Sonoran. 



Immediately north lies the subregion of the Sonoran (so termed by Dr. Mer- 

 riam) also known as the subregion of the Great Basin, including the larger part of 

 Inyo, all of Mono, the larger portions of Modoc and Lassen and a small part of Plu- 

 mas. Here Acmceodef-a, Asida and EUodes abound. 



The California faunal region proper includes practically all the lowlands of the 

 State, the fertile valleys of southern California and the extensive valleys of the San 

 Joaquin and Sacramento, the lesser valleys along the coast and the foothills bordering 

 them. The fauna prevailing throughout these portions are so affiliated with Sonoran 

 forms, particularly toward the south as to warrant the designation of such portions as 

 Sonoran sub-regions, and by the extension of these forms into the foothills where 

 they have interbred with Boreal types through a series of ages genera characteristic of 

 both parent regions have been evolved. Omus, Brenmis (a cychrid subgenus), 

 Metrius, Promecognathtis, Pleocoma and Rosalia with others while more or less re- 

 lated to anjacent northern forms probably developed from a rich circumpolar fauna 

 under the influence of adaptation to environment. Omus occurs rather generally 

 throughout the state, and Metrius and Promecognathus similarly but less frequently in 

 the moist timber belt of the Coast Range, although an Alpine variety of Metritis is 

 found in the Sierras, and Brennus is confined to the coast. Many other examples 



