90 ELEMENTARY STUDIES IN INSECT LIFE 



is carpeted with moss, so in making this trap-door the 

 spider covers it with moss, an act for protection, for 

 when the door is closed no trace of the spider's hiding- 

 place is visible. If in the absence of the spider the moss 

 be removed from the door and the earth bared over con- 

 siderable space around the door, the spider will upon her 

 return carry moss across the open space and re-cover her 

 trap-door, making this not a protection but the most 

 conspicuous object on the situation. That which 

 prompts the wasp to drag the grasshopper only by the 

 antenna?, and which causes the spider to cover its trap- 

 door with moss, is termed instinct. Had the wasp and 

 the spider shown their ability to cope with changed con- 

 ditions, their actions would have been due to reason. 

 These instinctive actions are those which are performed 

 without learning or practice. 



Actions of the Newly Born. Instinct is, then., best il- 

 lustrated by the actions of the newly born forms. Young 

 wasps, just out of the pupa-case, though limp and almost 

 helpless, when disturbed protrude the sting and move 

 the abdomen about in various directions, in their en- 

 deavor to sting the disturber. They seem to perform 

 these acts as perfectly as do the mature wasps. Sting- 

 ing, then, is a purely instinctive act. The young cater- 

 pillar's first act (p. 14) after leaving the egg is to turn 

 around and eat the egg-shell. All the young caterpillars 

 of the swallowtail butterfly do this. Not one of them 

 before doing this has had an opportunity to be taught 

 this act. They do it instinctively. The origin of in- 

 stinct is an open question: some authorities believe 

 that the act of one individual repeated many times be- 

 comes a habit, and that this habit can be transmitted 



