146 CREATIVE EVOLUTION [chap. 



In order to get at this essential difference we must, 

 without stopping at the more or less brilliant light which 

 illumines these two modes of internal activity, go straight 

 to the two objects, profoundly different from each other, 

 upon which instinct and intelligence are directed. 



When the horse-fly lays its eggs on the legs or shoulders 

 of the horse, it acts as if it knew that its larva has to develop 

 in the horse's stomach and that the horse, in licking itself, 

 will convey the larva into its digestive tract. When a 

 paralyzing wasp stings its victim on just those points 

 where the nervous centres lie, so as to render it motionless 

 without killing it, it acts like a learned entomologist and a 

 skilful surgeon rolled into one. But what shall we say of 

 the little beetle, the Sitaris, whose story is so often quoted? 

 This insect lays its eggs at the entrance of the under- 

 ground passages dug by a kind of bee, the Anthophora. 

 Its larva, after long waiting, springs upon the male Antho- 

 phora as it goes out of the passage, clings to it, and re- 

 mains attached until the "nuptial flight," when it seizes 

 the opportunity to pass from the male to the female, and 

 quietly waits until it lays its eggs. It then leaps on the egg, 

 which serves as a support for it in the honey, devours the 

 egg in a few days, and, resting on the shell, undergoes its 

 first metamorphosis. Organized now to float on the honey, 

 it consumes this provision of nourishment, and becomes 

 a nymph, then a perfect insect. Everything happens as 

 if the larva of the Sitaris, from the moment it was hatched, 

 knew that the male Anthophora would first emerge from 

 the passage; that the nuptial flight would give it the means 

 of conveying itself to the female, who would take it to a 

 store of honey sufficient to feed it after its transformation; 

 that, until this transformation, it could gradually eat 

 the egg of the Anthophora, in such a way that it could 

 at the same time feed itself, maintain itself at the surface 



