ENEMIES AND THEIR INFLUENCE. 385 



formidable of our spider fauna, Eurypelma hentzii. (Plate V., Fig. 1.) I 

 have seen this insect in Texas hawking for its gigantic victim, which 

 showed by its hurried and excited action full consciousness of its peril as 

 it fled with eager and trembling speed before its pursuer. The late Pro- 

 fessor Buckley, of Austin, describes an encounter on Texas soil between 

 these two formidable creatures. 



The tarantula killer is a bustling, unquiet insect, always in motion, fly- 

 ing now here, now there, and when running on the ground its wings are in 

 a state of constant vibration. Should it discover a tarantula it begins in- 

 stantly to fly in circles in the air around its victim. The spider, as if 

 knowing its fate, trembles violently, standing up and making a show of 

 fight, but the resistance is feeble and of no avail. The spider's foe soon 

 discovers a favorable moment and darts upon the tarantula, whom it 

 wounds with its sting, and again commences flying in circles. The injured 

 spider is thrown into a tremor, and often becomes at once paralyzed, 

 though the influence of a second, and even a third, wound is sometimes 

 necessary. Sooner or later the spider becomes powerless when the victor 

 approaches, carefully feeling its way to see if its work has been effectually 

 done. It then begins to drag the tarantula into a hole which it has pre- 

 viously dug in the ground, wherein it is covered up after the deposition 

 of an egg.i The courage and address thus shown in assault upon so for- 

 midable an animal, and the strength and perseverance required for its sub- 

 sequent entombment, are of the higliest order and surely evoke admiration, 

 however much we may pity a foe doomed to so liard a fate as to be par- 

 alyzed, buried alive, and afterward devoured by a greedy grub. 



In estimating the ravages wrought among spiders by the various tribes 

 of wasps, it must be remembered that in the above and all like cases, the 

 mother wasp, although depositing but one egg in each nidus, has a num- 

 ber of eggs, more or less, to dispose of. As she never ceases her work 

 until every egg is duly dejjosited and its future offspring provided for, the 

 vast destruction carried into the aranead hosts during the period of ma- 

 ternal activity may better be imagined than expressed. 



IV. 



The thought had occurred to me while examining the contents of mud 

 daubs, that certain species of spiders were preferred by the wasps as pro- 

 vision, and that possibly certain species of wasps affect certain 

 Sefection ^^^'^^^' ^pecies. In case of the true Diggers, who store but a sin- 

 of Prey. ^^^ individual, there is no doubt a narrower range for selection, 

 and even a specific choice, as with the Tarantula killer and the 

 Fourspotted Elis. But not so with mud daubers. I have found every 



' Proceedings Ainer. Rnto. Soc. (Philadelphia), Vol. I., page 1.S8. See alfso an account by 

 Dr. G. T,iucccuni, Aiuer. Kntoniologist, Vol. I., No. G, page 111. 



