54 THE BEAUTIES OF NATURE chap. 



mann has proved by actual experiment. He 

 put one of these caterpillars in a tray, in 

 which he was accustomed to place seed for 

 birds. Soon a little flock of sparrows and 

 other small birds assembled to feed as usual. 

 One of them lit on the edge of this tray, and 

 was just going to hop in, when she spied the 

 caterpillar. Immediately she began bobbing 

 her head up and down iu the odd way which 

 some small birds, have, but was afraid to go 

 nearer. Another joined her and then another, 

 until at last there was a little company of ten 

 or twelve birds all looking on in astonishment, 

 but not one ventured into the tray ; while 

 one bird, which lit in it unsuspectingly, beat a 

 hasty retreat in evident alarm as soon as she 

 perceived the caterpillar. After waiting for 

 some time, Weismann removed it, when the 

 birds soon attacked the seeds. Other cater- 

 pillars also are probably protected by their 

 curious resemblance to spotted snakes. One 

 of the large Indian caterpillars has even ac- 

 quired the power of hissing. 



Among perfect insects many resemble closely 

 the substances near which thery live. Some 



