592 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



These nymphal sldns were collected January 6, 1915, on the roots 

 and trunks of alder trees overhanging Los Trancos Creek where 

 they had been probably since the preceding August, 



17. SOME LISTS OF ODONATA COLLECTED IN NEVADA AND CENTRAL 

 CALIFORNIA DURING 1913 AND 1914. 



The foUoAving pages are devoted to hsts by localities of Odonata 

 collected in California and Nevada by the writer during the summer 

 of 1914. 



My collectmg in Cahfornia comprised three trips. One during 

 June up the Napa River and up the Sacramento Valley to Tehama, 

 one dming July up the American River and about Lakes Dormer and 

 Tahoe, and a third during September up the San Joaquin Valley to 

 Bakersfield, thence to the vicinity of Los Angeles. 



Because of its great length north and south, because one border is 

 on the coast and one on the desert, and because its great Sierra holds 

 many northern forms, Cahfornia has the richest odonate fauna of 

 any of the Western States. 



Faunistically the State can be roughly divided into three sections, 

 though these are nowhere sharply defined. The entire western border 

 of the State for a -wddth of from 50 to 100 miles is occupied by the 

 Coast Ranges. These are mamly north and south ridges of about the 

 size and appearance of the AUeghanies of the eastern United States. 

 In the north these are heavily timbered. In the central parts of the 

 coast the timber is hght, and on the east slopes replaced by brush 

 (chaparral), while in the south, Los Angeles and vicinity, the timber is 

 fomid only in the narrow canyons. Throughout the entire length of 

 these Coast Ranges are numerous perennial streams, but in the south- 

 ern half of these mountains many of these streams are dry beds of 

 white sand in their lower coui*ses during the dry season. Tliis coast 

 region is characterized by several local coast species. 



The second great region is that of the valleys of the Sacramento and 

 San Joaquin. As these rivers empty into the Bay, their valleys are 

 connected by the Bay region and become a continuous plam 300 

 miles long and in places 50 miles broad. This is more level than a 

 Kansas prairie and is a dry region with summer temperatures of 

 90° to 120° F. It is farmed largely to grains and its cities are walled 

 about by great dykes, as it is subject to floods when the snows melt in 

 the momitains each sprmg. It is characterized by several Mexican 

 species which here reach their northernmost hmits. 



The third region is that of the great Sierra Range, which runs for 

 the greater length of the eastern side of the State. The passes over 

 this are from 7,000 to 8,000 feet above sea level and its snow peaks 

 tower from 11,000 to 14,000 feet. The west slope is 50 miles wide, 

 but yet so steep that the numerous rivers come down through can- 



