THE BLACK WIDOW SPIDER » 



By Fred E. D'Amotjr, Frances E. Becker, and Walker Van Riper 

 Research Laboratories, University of Denver 



[With five plates] 

 INTRODUCTION 



This study was undertaken somewhat in the nature of a summer 

 diversion. Our interest in the black widow spider was first aroused 

 by the work of Blair (1934) which received considerable publicity 

 during the winter and spring of 1934. When it was found that these 

 spiders were fairly numerous in and around Denver, and a search of 

 the literature indicated that many points concerning their life history 

 and the properties of their venom were not definitely established, a 

 modest research program devoted to their study seemed to promise 

 considerable enjoyment, even though the results might not have an 

 exceedingly great scientific value. Since we could hardly hope to 

 make a specialized study in any one particular field, we decided to 

 explore all of them a little. In consequence, this paper gives findings 

 covering various aspects of the problem. In the first part the appear- 

 ance of the spider is described, and observations concerning its natural 

 history recorded. In the second, studies concerning the toxicity of 

 the venom, its chemistry, immunology, toxicology, and pathology 

 are reported. Most of the experiments herein reported were carried 

 out during the summer of 1934. However, delay in publication per- 

 mits inclusion of certain observations and experiments conducted 

 during 1935. The total number of spiders collected has been about 

 6,500, and some 500 rats have been used. 



The literature up to 1932 has been adequately reviewed by Bogen 

 (1932); reference to other important work will be made in the appro- 

 priate place. 



NATURAL HISTORY 



Spiders have a fife that is vivid and intense, though so unobtrusive 

 that we usually do not see them, or at most pay little attention to 

 them. Specialists find them fascinating as a group because of their 

 anatomical peculiarities, their production of silk, and their habits of 



• Reprinted by permission, with some omissions, from The Quarterly Review of Biology, vol. 11, No. 2, 

 June 1936. 



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