2 PEOCEEDIXGS OF THE NATION" AL MUSEUM vol. 73 j 



Before attempting the present synopsis the writer was sent by 

 the Bureau of Entomology to the States of Louisiana, Texas, and | 

 Arizona to investigate scorpion conditions and make collections. ,; 

 While there something was learned of the habits of scorpions and 

 of man^s encounters with them; also many live specimens were | 

 captured. Various persons in the Southwest aided the writer in < 

 securing information and in collecting specimens. Special mention | 

 should be made of the following: Mr. E. V. Walter, Bureau of j 

 Entomology, San Antonio, Tex.; Mr. H. B. Parks, apiculturist, 

 State Apicultural Ecsearch Laboratory, near San Antonio, Tex.; 

 Mr. V. L. Wildermuth, Bureau of Entomology, Tempe, Ariz.; Mr. 

 E. E. Russell, Bureau of Entomology, Yuma, Ariz., and several 

 members of the Bureau of Entomology staff at Dallas, Tex. 



CONCERNING SCORPIONS IN GENERAL 



Scorpions are large, more or less crablike, arachnids of very ancient 

 origin. By leading authorities they are considered as the most an- 

 cient and generalized of the true arachnids. They have the body 

 divided into two definite regions, the cephalothorax and the abdomen. 

 The latter, however, has the posterior part greatly narrowed and 

 formed into a so-called "tail." This region, known as the post- 

 abdomen, bears on its distal segment the sting, the only weapon 

 which the scorpion has to make itself dreaded by man. 



The legs of a scorpion are eight in number throughout life. They 

 are clawed at the end and are ail similar. The palpi are greatly 

 enlarged, and the last two segments form a powerful pinching struc- 

 ture known as the chelae. The true jaws, which should be known as 

 the chelicerae, are much smaller structures than the chelae and are 

 partly concealed from above by the front edge of the carapace, the 

 hard covering of the cephalothorax. 



The organs of special senses are poorly represented ; however, the 

 eyes are conspicuous and of two kinds. There is a pair of large 

 eyes situated on the sides of a turret or tubercle near the middle of 

 the dorsal surface of the cephalothorax and several smaller eyes, or 

 ocelli, situated on the lateral margins. The more important struc- 

 tures used in taxonomy are given in the accompanying illustration. 



Scorpions are found in greatest abundance in tropical and sub- 

 tropical countries. Only a few species range far into the temperate 

 zones and none extend across either of these zones. The taxonoraic 

 work on the United States species has been done chiefly by Wood, 

 Marx, and Banks. In the past 20 years no extended paper has 

 appeared dealing with our species. The subject of the control of 

 scorpions and of the treatment of their stings will be dealt with in 

 a subsequent paper. 



