A NATURALIST IN BRAZIL 



few deserted tubes, and in each cell they had placed an egg and 

 some honey. 



Anyone who has ever observed a hornet at work — and to watch 

 the large, handsome "Cavallo do cae" is truly such a treat as only 

 Brazil can offer — will always receive the impression that the insect 

 is acting with the most subtle consideration. And yet the insect 

 never sees the result of all its labours, never learns that one day a 

 larva, which needs fresh food, creeps out of the apparently lifeless 

 egg; so that an innate instinct alone can tell the insect what to do. 

 It cannot be guided by recollections of its own youth, for the larva 

 was not in existence when its mother fell upon her prey, and she 

 herself never saw, nor has the newly emerged hornet seen, how 

 the victim should be overpowered, and where the sting should be 

 inserted in order to paralyse it. And yet at the very first attempt 

 the hornet strikes accurately at the nerve-centre, which in the 

 spider lies in the thorax, and, what is more, on the underside of the 

 thorax. Hornets which seek other prey seem in each case to under- 

 stand the anatomy of their victim; in the first place, they select 

 only such flies, beetles, grasshoppers, etc., as have a readily accessible 

 nerve-centre, and secondly, they understand in each case precisely 

 where the sting should be inserted ; and in each species of wasp or 

 hornet the length of the sting is precisely that best adapted to the 

 anatomy of its victim. 



Again, the larvae know nothing of the significance of the various 

 viscera of their victims, though they are careful to respect the vital 

 organs. They too have no example to follow, no teacher ; the instinct 

 is inborn, and precisely because their behaviour is instinctive it 

 works with absolute reliabihty. 



Certain of the Hornets supply their brood with small insects, such 

 as beetles and flies, and a number of these would have to be brought 

 to the nest and stored there, since a single victim would not suffice 

 to nourish the larva. So here we see the beginning of another 

 method, which resembles that followed by the birds and mammals. 

 The mother does not die after laying the eggs, but survives until 

 her larvae are fully developed, so that she can at any time enter 

 their nursery, in order to see that all is well with them, and bring 

 them fresh food. 



Here, then, even among the insects, like a groping ray of sunshine, 

 we see the first attempts at a common life of parents and offspring. 

 286 



