64 STRICTLY INCOG. 



serve the visits of their suspicious friend, and to note their 

 coincidence with the frequent mysterious disappearance of 

 a fellow-townswoman, evaporated into space, like the miss- 

 ing young women in neat cloth jackets who periodically 

 vanish from the London suburbs. In proportion as their 

 reasonable suspicions increased, the termites would care- 

 fully avoid all doubtful looking mantises ; but, at the same 

 time, they would only succeed in making the mantises 

 which survived their inquisition grow more and more closely 

 to resemble the termite pattern in all particulars. For 

 any mantis which happened to come a little nearer the 

 white ants in hue or shape would thereby be enabled to 

 make a more secure meal upon his unfortunate victims ; 

 and so the very vigilance which the ants exerted against 

 his vile deception would itself react in time against their 

 own kind, by leaving only the most ruthless and indistin- 

 guishable of their foes to become the parents of future 

 generations of mantises. 



Once more, the beetles and flies of Central America 

 must have learned by experience to get out of the way of 

 the nimble Central American lizards with great agility, 

 cunning, and alertness. But green lizards are less easy to 

 notice beforehand than brown or red ones ; and so the 

 lizards of tropical countries are almost always bright green, 

 with complementary shades of yellow, grey, and purple, just 

 to fit them in with the foliage they lurk among. Every* 

 body who has ever hunted the green tree-toads on the leaves 

 of waterside plants on the Riviera must know how difficult 

 it is to discriminate these brilliant leaf-coloured creatures 

 from the almost identical background on which they rest. 

 Now, just in proportion as the beetles and flies grow still 

 more cautious, even the green lizards themselves fail to 

 pick up a satisfactory livelihood ; and so at last we get that 

 most remarkable Nicaraguan form, decked all round with 



