34 SANTAREM. Chap. I. 



of at least half a mile to procure the kind of fly, the 

 Mottica (Hadaiis lepidotus), with which it provisions its 

 cell. I often noticed it to take a few turns in the air 

 round the place before starting ; on its return it made 

 without hesitation straight for the closed mouth of the 

 mine. I was convinced that the insects noted the bear- 

 ings of their nests and the direction they took in flying 

 from them. The proceeding in this and similar cases (I 

 have read of something analogous having been noticed in 

 hive bees) seems to be a mental act of the same nature 

 as that which takes place in ourselves when recognising 

 a locality. The senses, however, must be immeasur- 

 ably more keen and the mental operation much more 

 certain in them than it is in man ; for to my eye there 

 was absolutely no land-mark on the even surface of 

 sand which could serve as guide, and the borders of the 

 forest were not nearer than half a mile.- The action 

 of the wasp would be said to be instinctive ; but it 

 seems plain that the instinct is no mysterious and unin- 

 telligible agent, but a mental process in each individual, 

 differing from the same in man only by its unerring 

 certainty. The mind of the insect appears to be so con- 

 stituted that the impression of external objects or the 

 want felt, causes it to act with a precision which seems 

 to us like that of a machine constructed to move in a 

 certain given way. I have noticed in Indian boys a 

 sense of locality almost as keen as that possessed by 

 the sand-wasp. An old Portuguese and myself, accom- 

 panied by a young lad about ten years of age, were 

 once lost in the forest in a most solitary place on the 

 banks of the main river. Our case seemed hopeless, 



