418 EVOLUTION AND ANIMAL LIFE 



pieces of meat, for which there was a great competition among them, 

 I managed to entice a young duck into snatching up one of the little 

 frogs. Instead of swallowing it, however, it instantly threw it out of 

 its mouth, and went about jerking its head, as if trying to throw off 

 some unpleasant taste." 



Certain other insects which are without special means of 

 defense and are not at all formidable or dangerous, are yet so 

 marked or shaped and so behaved as to present a curiously 

 threatening appearance. The large green caterpillars of the 

 sphinx moths have a curious rearing-up habit which seems to 



simulate threatened 

 attack (Fig. 261). 

 They have, too, a 

 great pointed spine 

 or horn on the 

 back of the pos- 

 terior tip of the 



FIG. 261. A "tobacco-worm," larva of the sphinx moth, body which has a 

 Phlegethontius Carolina, showing terrifying attitude. most formidable 



appearance, but is, 



as a matter of fact, not at all a weapon of defense, being quite 

 harmless. Numerous stingless insects, when disturbed, wave 

 about the hind part of the body or curl it over or under, much 

 as stinging insects do, and seem to be threatening to sting. 

 The striking eye spots of many insects are believed by some 

 entomologists to be of the nature of terrifying markings. Mar- 

 shall tried feeding baboons a full-grown larva (about seven 

 inches long) of the sphinx moth, Cheer ocampa osiris. The 

 larva has large strongly colored eye spots and is 



" remarkably snakelike, the general coloring somewhat recalling that 

 of the common puff-adder, Bitis arietans. The female baboon ran for- 

 ward expecting a titbit, but when she saw what I had brought she 

 flicked it out of my hand on to the ground, at the same time jumping 

 back suspiciously: she then approached it very cautiously, and after 

 peering carefully at it at the distance of about a foot she withdrew in 

 alarm, being clearly much impressed by the large blue eyelike mark- 

 ings. The male baboon, which has a much more nervous tempera- 

 ment, had meanwhile remained at a distance surveying the proceedings, 

 so I picked up a caterpillar and brought it towards them, but they 



