6 THE EVOLUTIONIST AT LARGE. 



and the cerebellum which are superadded in 

 us mammals upon the simple sense-centres 

 of lower creatures. Besides the eye, with its 

 optic nerve and optic perceptive organs be- 

 sides the ear, with its similar mechanism- 

 mammalian lords of creation have a higher 

 and more genuine brain, which collects and 

 compares the information given to the senses, 

 and sends down the appropriate messages to 

 the muscles accordingly. Now, bees and flies 

 and ants have got much the same sort of 

 arrangement, on a smaller scale, within their 

 tiny heads. On top of the little knots which 

 do duty as nerve-centres for their eyes and 

 mouths, stand two stalked bits of nervous 

 matter, whose duty is analogous to that of 

 our own brains. And that is why these 

 three sorts of insects think and reason 

 so much more intellectually than beetles or 

 butterflies, and why the larger part of them 

 have organised their domestic arrangements 

 on such an excellent co-operative plan. 



\Vc know well enough what forms the 



