AUGUST 211 



jump nearly out of his skin with terror at the flutter of a 

 bird in the wayside fence. We may recognise heredity 

 in these traits. As the primitive horse learned to suspect, 

 by the rustle of leaves and grass, the presence of some 

 lurking beast of prey, so primitive man acquired an 

 indelible dread and horror of every form of serpent and 

 stinging insect, and the ancestral impulse of avoidance or 

 flight takes effect before the control of reason and experi- 

 ence can be brought into play. You may test this any 

 day in early summer. Having found a tomtit's or wren's 

 nest, and ascertained that the bird is sitting on her eggs, 

 take a friend and ask him to put in a finger to count the 

 eggs. An angry hiss will be uttered by the little mother 

 a note reserved for moments of imminent peril and 

 your friend, unless he is better instructed than most 

 people, and prepared for that result, will snatch his hand 

 away in a momentary spasm of dread. Herein is a double 

 example of congenital instinct. Compound reflex action 

 in the bird makes it hiss involuntarily, and causes the 

 man to avoid the danger suggested by the hiss, which 

 is immemorially associated with the presence of a 

 serpent. 



This train of thought was started by a little incident in 

 my garden one morning lately August 15. I was plant- 

 ing a consignment of cyclamens from Italy, when a winged 

 insect like a gigantic wasp swooped straight for me and 

 passed close to my ear. I gave a convulsive start, and 

 candidly admit to a momentary sensation of terror. 

 Next moment reason reasserted itself, and recognising 

 the creature, not as a true wasp or hornet, but as one of 

 the most interesting of British insects, the yellow wood- 

 wasp (Sirex gigas), I knocked it down with my cap and 



