IN VERTEBRATES 59 



striped " blazer " of the Wasp, and the spotted jacket of the 

 Lady- Bird. Unless very hard pressed by hunger it appears 

 that the foes of animals so coloured and marked give them a 

 wide berth. But without careful observation and experiment 

 it would remain an open question whether this resulted from 

 Instinct or Intelligence, or a mixture of the two. The cases 

 which have so far been properly investigated appear to prove 

 that Intelligence here comes into play, and that a young animal 

 has to learn from experience that some things are good to eat 

 and others not. The thorough and long-continued researches 

 of Lloyd Morgan upon artificially - hatched chicks definitely 

 prove that they at least have to acquire such useful knowledge 

 for themselves. He thus describes (in Animal Behaviour) how 

 some of his chicks learnt that alternate bands of black and 

 orange, as possessed by the caterpillars of the Cinnabar Moth, 

 are associated with disagreeable sensations: "The following 

 experiment was made with young chicks. Stripes of orange and 

 black paper were pasted beneath glass slips, and on them meal 

 moistened with quinine was placed. On other plain slips meal 

 moistened with water was provided. The young birds soon 

 learnt to avoid the bitter meal, and then would not touch plain 

 meal if it was offered on the banded slip. And these birds, 

 save in two instances, refused to touch cinnabar caterpillars, 

 which were new to their experience. They did not, like other 

 birds, have to learn by particular trials that these caterpillars are 

 unpleasant. Their experience had already been gained through 

 the banded glass slips; or so it seemed. I have also found that 

 young birds who had learnt to avoid cinnabar caterpillars left 

 wasps untouched." 



NEST- BUILDING IN BIRDS. There can be no reasonable doubt 

 that in its main features the nest-building of birds is a matter of 

 instinct. One of the best proofs of this is afforded by cases 

 where individuals kept in captivity from the time of hatching, 

 under conditions which excluded the possibility of instruction or 

 imitation, have nevertheless constructed nests of the kind proper 

 to their species. Further experiments, however, are much to be 

 desired, especially on birds which indulge in architecture of such 

 characteristic kind as to be quite unmistakable. It would, of 

 course, be necessary to make the nesting conditions in such cases 

 as natural as possible. Other instincts, tending to the benefit 



