ECONOMIC AND MEDICAL IMPORTANCE 251 



about a third as large as their mates, must search for the females 

 during the brief mating season. In this weaker sex the chelicerae 

 are very small, and the creatures are reported never to bite. To the 

 females must be given credit for all poisonous injury to animals and 

 man. 



In spite of their great reputation, the females are timid. They 

 ordinarily make no effort to bite, even when subjected to all kinds 

 of provocation. Although charged with viciousness, they are never 

 aggressive and make no effort to attack, preferring instead to retreat 

 and lie perfectly still. The danger lies in the fact that, because they 

 live in abundance near man, they may be accidentally squeezed 

 against the body in some way. They lie hidden in the folds of cloth- 

 ing, or in shoes. When a body contact is established under these 

 exceptional conditions, the black widow bites in self-defense. 



It is in the old-fashioned outdoor privies that the black widow 

 is particularly dangerous. Ideal sites for nests and webs are found 

 under the seats, and a large fly population provides plenty of food. 

 The threads of the web often fill large areas beneath the seats, and 

 are sometimes touched by parts of the body when the houses are 

 in use. A gentle brushing of the web initiates the normal response 

 of the spider to the presence of insect prey; it rushes to the site 

 and bites the object vigorously, treating it in exactly the same way 

 as it would a large insect. Most victims of this type of black widow 

 are males, and the injury is centered on the external genitalia. 



The symptoms in man following the injection of the venom are 

 now very well known, chiefly through the splendid work of Dr. 

 Emil Bogen of California, in a state where a high percentage of 

 bites have occurred. The wound causes a trivial initial pain com- 

 parable to the prick of a needle, and leaves two tiny red marks at 

 the site of entrance of the two chelicerae. Almost immediately there 

 develop acute local pains, which reach their maximum intensity 

 within half an hour in most instances, and persist for a number of 

 hours. Indeed, sharp pain is a prime symptom of the bite; it has 

 been described as "intense, violent, agonizing, exquisite, excruciat- 

 ing, griping, cramping, shooting, lancinating, aching and numbing, 

 and was either continuous and incessant, or paroxysmal and inter- 

 mittent." The pain moves gradually from the wound to other parts 

 of the body, and finally concentrates in the abdomen and the legs. 



In addition to the intense pain, many other symptoms have been 

 described, most of these being consequences of the direct action of 

 the venom on the nerve centers. Nausea and vomiting, faintness, 



