1921] The Age of Insects 47 



plex chain reflex which causes the adult female insect to deposit her 

 eggs so that the newly hatched young will find an abundance of food 

 close at hand for its sustenance. These relations are easy to under- 

 stand in those insects where the young and the adults feed upon the 

 same host but they become increasingly difficult to understand as we 

 pass to those adults which either do not feed or feed upon an entirely 

 different substance. For example the adults of the order Lepidoptera, 

 the butterflies and moths, feed on the nectar of plants for the most 

 part yet their larvae feed upon roots, stems, leaves or seeds of plants or 

 on animal products. The eggs must be laid in close proximity to such 

 food or the larvae would perish and the species would vanish from the 

 earth. What is the mechanics that brings this very desirable conclu- 

 sion? We may answer that this series has become hereditarily in- 

 stinctive but when we do so we are merely clothing our ignorance in a 

 mass of verbiage. 



The climax in this series of complex reflexes is reached among the 

 solitary wasps to which I have alluded in another connection. This 

 complex may be pictured briefly and in a somewhat generalized way 

 as follows. The female wasp digs a burrow in the soil. She goes 

 away and searches until she finds the proper prey, be it cicada, horsefly, 

 caterpillar or spider. She pounces upon it and stings it in the thoracic 

 ganglia so that the prey will be paralyzed but not killed, for if the prey 

 were killed it would decay before the egg hatched and the young larva 

 would starve to death. She drags or carries the prey back to the bur- 

 row, often a considerable distance, and by means of some sense that is 

 beyond human understanding she locates the burrow and deposits her 

 prey; lays her egg; closes the burrow and, wonder of wonders, has the 

 time and the patience to conceal the entrance of the burrow by making 

 it look like the surrounding territory. If in hard ground she seeks out 

 a small pebble and pounds the loose dirt down until it blends in with 

 the surrounding territory, or if in a tidal flat with a crust of salt she 

 finds a bit of crust to cover the entrance. Such in brief is the story, 

 but who has the insight to unravel the maze of ecological factors that 

 are woven into such a complex? 



Another series of ecological adaptations that is so common that 

 it causes no comment is the relation between poUination and insects. 

 Here we are confronted with a case of parallel development that if it 

 were not so common or if it existed only in the South Sea Islands would 

 be one of the wonders of the age, but because we see it everywhere 

 about us, because it is the rule rather than the exception, it arouses 



