of one of these animals. The real danger of the spread of infection 

 lies in the dissemination of infected fleas. As has been shown by the 

 recent campaign against these ground squirrels, carried on by the U. S. 

 Public Health and Marine Hospital Service, eradication of this pest 

 depends largely on persistent work of the individual. 



This group of long-eared gray ground squirrels has a wide range, 

 being found throughout the State. Several species and several varieties 

 of each have been recognized. Each variety or subspecies occupies a 

 fairly well-defined region of the State, so that they can usually be dis- 

 tinguished by the locality in which they are found. The northern coast 

 form is known as the Douglas ground squirrel (Citellus douglasi) 

 that of the interior valleys, as the California ground squirrel (Citellus 



FIG. 1. Two varieties of the common "digger" ground squirrel of California, found 

 throughout the State. The squirrel above is the Douglas ground squirrel (Citellus 

 douglasi), found along the coast north of San Francisco Bay; the one below is the 

 California ground squirrel (Citellus beecheyi beecheyi), the common ground squirrel 

 of the interior valleys and the carrier of bubonic plague. 



beeckeyi beecheyi) ; and that of southern California, as the Fisher 

 ground squirrel (Citellus beecheyi fisheri) . 



In the extreme northeastern corner of the State and to some extent 

 in the northern part, a smaller brown ground squirrel is found in 

 abundance. It is known as the Oregon ground squirrel (Citellus 

 oregonus) . The ground squirrel of the desert is much smaller than the 

 common "digger" squirrel and is striped. It is called the desert or 

 round-tailed ground squirrel (Citellus tereticaudus) . A small striped 

 form belonging to another genus (Ammospermophilus) is found to a 

 limited extent in the San Joaquin Valley, and a variety of the same 

 species in the rocky places in the deserts and foothills bordering the 

 deserts. These forms are known as the Nelson ground squirrel and the 

 Antelope ground squirrel. Neither are abundant enough to be of great 

 economic importance. Golden-mantled ground squirrels (Callospermo- 

 philus sp.), more often called red-headed chipmunks, are mountain 

 species and seldom give trouble (Fig. 2). 



