A STUDY OF MIMICRY 7 



They fly up at yoiii" approach, whiz off a rod or so, 

 and alight. Can you see them? They are col- 

 ored so nearly like the sands they live upon that 

 detection of one at rest is almost impossible. On 

 yonder grassy bluff, a stone's throw away, you will 

 find none of them, but other kinds equally, or 

 almost equally, lost to sight by their harmony with 

 their surroundings. What chance of life for either 

 if they suddenly changed places ? They would be 

 so conspicuous that every passing bird or other 

 insectivorous creature would sight them. Of course 

 these protective colors have been gained by slow 

 steps. Every grasshopper that found its preferred 

 food among the sands was liable to be eaten. In 

 the long run just those would be eaten which were 

 most easily seen. One which varied in coloring in 

 never so small a degree, so as to be less easily seen 

 than his brother, would live to perpetuate his kind, 

 and his brother come to an untimely end ; the pro- 

 geny would show the fortunate variation, and be 

 more likely to be spared to transmit in increased 

 volume the probability of the happy coloring. 

 Given, then, a brood of grasshoppers that find 

 their preferred food in sandy spots, and unless 

 other and more powerful forces act upon them it 

 must result, from their liability to be eaten by 



