Thk Cows that Ants Milk 23 



lielcl-voles, can hardly be cdir.batcd with any hope 

 of success ; while locusts and Colorado beetles 

 devastate our crops with practical impunity. 



When it conies to aphides, we are cjuite unable 

 to cope witii the infinite numbers of our infmi- 

 tesimal foes ; and if we taUe the microscopic 

 creatures wliich cause cholera, typhoid fever, and 

 other zvmotic diseases, we may keep out of their 

 wav, it is true, or mav isolate the objects in whicli 

 they breed and store their ijerms, but we are 

 practically without means to kill or hurt them. 

 The larger the foe, the more easily is he met ; tiie 

 smaller our enemy, the more ditticult is he to 

 extirpate. We killed off tlie American buffalo (or 

 bi'^on) in a sini;le f^eneration ; a thousand years 

 would probably fail to kill off the insignilicant little 

 aphides that infest our roses. 



hi the case of one member of the family at 

 least the experiment has been tried on a j^ij^antic 

 scale in France, and as yet with comparatively 

 small results. For the ch'eaded pliylloxera which 

 attacks tlie vines is, in fact, an aphis ; and though 

 iuunense rewards have been olfered by the Frencli 

 Assembly for any good remedy aj^ainst phylloxera, 

 the only successful plan as yet proposed has been 

 that of plantini^ healthier and sturdier American 

 vines, which resist the little beast a j^ood deal better 

 than the ellete and woiii-out Furopean species. 

 l»iit many other members of the familv waj^e war 

 with distinj^uisJR'd success a-^ainst the British farmer. 

 Tile little black " colliers ' wliich attack our bean 



