POISONOUS INSECTS AND THEIR RELATIVES 405 



The whole question, it seems to the writer, is fairly and 

 conservatively summed up by McCook in the following 

 words, so pertinent to the subject that we quote them in 

 full: "Reasoning from analogy of other venomous 

 animals, serpents for example, it is probably true that 

 much of the effect of spider venom depends upon the con- 

 dition of the spider itself as to degree of irritation, etc., 

 at the time when the stroke is given. On the other hand, 

 the physical condition of the person bitten also largely 

 determines the effect of the bite. That which is harmless 

 to one individual we know is often injurious or fatal 

 to another; and that which at one period of life may 

 produce serious results, at another time is comparatively 

 harmless. It is, therefore, probably true that there are 

 a few of our indigenous spiders, as Latrodectus mactans and 

 Phidippus morsitans, which at certain times may inflict 

 an injury upon certain individuals which may be serious 

 and even fatal. But in the great majority of cases, 

 there is no more, and indeed is less, reason to apprehend 

 danger from a stroke or bite of a spider than from the 

 sting of a bee or probe of a mosquito. 



"Inthecase of the immense creatures (Mygalidae) known 

 as tarantulas, the matter, of course, is different. It would 

 be strange indeed if such large animals, with so formidable 

 fangs and such a considerable supply of venom in the 

 poison glands, should not be able to inflict a serious wound. 

 The cases which have been reported to me of injury result- 

 ing from the stroke of these large spiders, I consider suffi- 

 cient to establish this fact, and to warrant the general 

 feeling that they are animals to be handled with great 

 care." 



