THE SURVIVAL OF THE FITTEST 387 



ance; the shining black color of flight was now dull, 

 and the yellow bars had turned to a dirty white. 

 I thought I would examine them to see what had 

 happened and to fix the guilt upon a suspicious 

 looking spider. When I reached my hand towards 

 them in a flash the whole lot flew away and began 

 their trembling flight. 



They attach themselves in considerable num- 

 bers, crowding so close on the moss that they 

 touch each other; in fact I once counted twenty- 

 five of them within a space of ten inches. At 

 times they partly bury themselves in the moss and 

 the irregular wing stripes look almost exactly like 

 the twisted strands among which they are hiding. 

 The ground color of the insect is not at all con- 

 spicuous and I have no doubt but that the whole 

 arrangement is a trick to deceive its enemies into 

 supposing it is only part of the long moss. So 

 closely do they mimic their environment that I 

 always have to look closely to be sure whether 

 they are on the moss or not, and so completely 

 do they simulate death that I am constantly being 

 deceived into thinking that they must be dead. 

 Their color returns at once when they recommence 

 their flight. 



