98 INSTINCT 
With animals which go through a profound metamorphosis 
in the course of their development we find correspondingly 
great changes in instinctive behavior. Nothing could be 
more dissimilar than the instincts of the stealthy dragon- 
fly nymph which prowls among the débris at the bottom of 
ponds and streams for its food, and the graceful and rapid 
darting of the full fledged dragon-fly as it chases its prey 
through the air. The transition between these two stages 
is very abrupt. When ready for its final moult the dragon- 
fly nymph crawls upon the stem of some plant or upon a 
stone, its skin splits down the back, and out comes the imago, 
which needs only to dry its wings a little to be ready for its 
vita nuova in the world of sunshine. The difference between 
the behavior of the crawling, gnawing caterpillar and the 
active honey sucking butterfly; of the helpless wriggling 
grub and the honey bee; of the free swimming larva and the 
worm that burrows in the sand of the seashore are instances, 
out of thousands that might be given, of the great differences 
in instinctive behavior at different periods of life in forms 
which undergo marked metamorphoses in structure. 
Where animals are hatched in the form of the adult we find 
little change in instinct. The young trap door spider, accord- 
ing to Moggridge, constructs its tiny tubular dwelling with its 
ingeniously fitted trap door in almost a perfect miniature of 
the adult nest. Montgomery finds that the young of the 
orbweavers Epetra scolpetaria and E. marmorea spin, at their 
very first attempt, a diminutive web of the same degree of 
perfection as that of the full grown spider. Here, as in the 
case of the amphipod previously described, the young closely 
resemble the older individuals. Where the change of form 
is greater, as in insects with a gradual or incomplete meta- 
morphosis, there is a gradual change of instinct. The be- 
havior of the tadpole graduates insensibly into the very 
