SOME ARACHNIDA FROM CALIFORNIA. 



BY NATHAN BANKS. 



Plates XXXVIII-XLI. 



The following pages include a list of spiders and other 

 Arachnida sent me for determination by the California 

 Academy of Sciences, together with other Californian 

 material received from several collectors. 



The arachnid fauna of California is undoubtedly very 

 large, so that this list is far from complete; yet it is full 

 enough to show some of the more striking peculiarities of the 

 fauna._ The abundance of Pseudoscorpions and Phalangid£e 

 is not equaled elsewhere in the country. There is a larger 

 proportion of Thomisidas and Drassidas than is found in the 

 eastern parts of the country. In Southern California there 

 are a few species of a tropical aspect. In the northern parts, 

 particularly from Mount Shasta, there are various spiders 

 common to the northern parts of this country and of Europe. 

 It is a notable fact that these northern spiders extend 

 farther southward in California than they do in the Eastern 

 States. Since Atlantic latitudes are colder than Pacific 

 ones, it follows that these spiders flourish in California in a 

 much warmer average temperature than they are accus- 

 tomed to in the East. 



Altogether there are two hundred and six Arachnida re- 

 corded in this list; one hundred and fifty-three spiders, and 

 fifty-three of the other groups. The spiders belong to 

 twenty-one families, eight of which are represented by but 

 one species each. The largest family is the Attidas with 

 twenty-four species; then follows the Theridiid^ with 

 twenty; the Epeiridse and Thomisidse each have eighteen. 

 Of the other groups the Acarina and Phalangida have each 

 nineteen species. 



(i) [ 331 ] November 29, 1904. 



