Chiracanthium nutrix is a common European species of the family Clubionidæ, concerning which there is much conflicting testimony. Among the reports are two by distinguished scientists whose accounts of personal experiences cannot be ignored. A. Forel allowed a spider of this species to bite him and not only was the pain extreme, but the general symptoms were so severe that he had to be helped to his house. The distinguished arachnologist, Bertkau reports that he, himself, was bitten and that an extreme, burning pain spread almost instantaneously over the arm and into the breast. There were slight chills the same day and throbbing pain at the wound lasted for days. While this particular species is not found in the United States, there are two other representatives of the genus and it is possible that they possess the same properties. We are unaware of any direct experimental work on the poison.
Epeira diadema, of Europe, belongs to a wholly different group, that of the orb-weavers, but has long been reputed venomous. Kobert was able to prepare from it an extract whose effects were very similar to that prepared from Latrodectus, though feebler in its action. Under ordinary circumstances this spider is unable to pierce the skin of man and though Kobert's results seem conclusive, the spider is little to be feared.
Phidippus audax (P. tripunctatus) is one of our largest Attids, or jumping spiders. The late Dr. O. Lugger describes a case of severe poisoning from the bite of this spider and though details are lacking, it is quite possible that this and other large species of the same group, which stalk their prey, may possess a more active poison than that of web-building species.
Summary—It is clearly established that our common spiders are not to be feared and that the stories regarding their virulence are almost wholly without foundation. On the other hand, the chances of secondary infection from the bites of some of the more powerful species are not to be ignored.
Probably all species possess a toxin secreted by the poison gland, virulent for insects and other normal prey of the spiders, but with little or no effect on man.
There are a very few species, notably of the genus Latrodectus, and possibly including the European Chiracanthium nutrix and Epeira diadema, which possess, in addition, a toxalbumen derived from the general body tissue, which is of great virulence and may even cause death in man and the higher animals.
THE PEDIPALPIDA OR WHIP-SCORPIONS
The tailed whip-scorpions, belonging to the family Thelyphonidæ, are represented in the United States by the giant whip-scorpion Mastigoproctus giganteus ([fig. 10]), which is common in Florida, Texas and some other parts of the South. In Florida, it is locally known as the "grampus" or "mule-killer" and is very greatly feared. There is no evidence that these fears have any foundation, and Dr. Marx states that there is neither a poison gland nor a pore in the claw of the chelicera.