370 ARACHNIDA — ARANEAE chap. 



formosa, which preys upon the gigantic spider Eiirypelma hentzii, 

 wrongly styled in America the " tarantula," but really belonging 

 to an entirely different family, the Aviculariidae. 



Fabre's most interesting researches have established the fact 

 that the instinct of the wasp leads it to sting the spider in a 

 particular spot, so as to pierce the nerve ganglion in the thorax. 

 The precision with which this is effected is absolutely necessary 

 for the purpose of the insect. If stung elsewhere, the spider is 

 either incompletely paralysed, or it is killed outright, and thus 

 rendered useless as food for the future larvae of the wasp. On 

 the one hand, therefore, the Tarantula has acquired the habit of 

 striking the wasp in the only point where its blow is instan- 

 taneously fatal, while on the other the wasp, with a different 

 object in view, has been led to select the precise spot where its 

 sting will disable without immediately destroying the spider. 

 The latter case is, if anything, the more extraordinary, as the 

 insect can hardly have any recollection of its larval tastes, and 

 yet it stores up for progeny, which it will never see, food which 

 is entirely abhorrent to itself in its imago state. 



Spiders taken from the egg-nests of wasps by M'Cook survived, 

 on the average, about a fortnight, dm-ing which period they 

 remained entirely motionless, and would retain any attitude in 

 which they were placed. 



There are many animals which either habitually or occasionally 

 feed upon spiders. They are the staple food of some humming- 

 birds, and many other birds appear to find in them a pleasing varia- 

 tion on their customary insect diet. These creatures, moreover, 

 are destructive to spiders in another way, by stealing the material 

 of their webs, and especially the more closely textured silk of their 

 egg-cocoons, to aid in the construction of their nests. M'Cook 

 has observed this habit in the case of Vireo noveborocensis, and he 

 states, on the authority of others, that the "Plover" and the "Wren" 

 are addicted to it. The smaller species of monkeys are extremely 

 fond of spiders, and devour large numbers of them. They are 

 said, moreover, to take a mischievous delight in pulling them in 

 pieces. Armadillos, ant-eaters, snakes, lizards, and indeed all 

 animals of insectivorous habit, draw no distinction between 

 Insecta and Arachnida, but feed upon both indiscriminately. The 

 army ants, so destructive to insect life in tropical countries, 

 include spiders among their victims. These formidable insects 



