642 Reflexes, Instincts, and Intelligence 



mensal and communal life, and various other specialized phases of insect 

 life, is described often in considerable detail. So that reference to these 

 accounts may suffice in this place in lieu of repeating these descriptions or 

 of adding new ones. For miscellaneous examples of insect instincts, or be- 

 havior satisfying our definition of instinct, the reader may refer to the accounts 

 of the egg-laying of bot-flies on p. 337, of the ham-fly on p. 348, of the bee- 

 moth on p. 379, of the monarch butterfly on p. 452, of the California oak- 

 moth on p. 407, of the fig Blastophaga on p. 487, of Tremex and Thalessa on 

 pp. 467 and 483, of gall-flies and their guests on p. 468, of the lace- wing fly 

 on p. 228, of Mantispa on p. 234, of the blister-beetles on p. 290; accounts 

 of the building of protecting larval cases or tents by caddis-flies on p. 240* 

 by leaf-rollers on p. 375, by bag-worms on p. 385, and by tent-caterpillars 

 on p. 415; the account on p. 230 of the ant-lion and its pit, on p. 396 of 

 the "going stiff" of the inch-worms, on p. 394 of the threatening of the 

 puss-moth larva, on p. 107 of the tunnel-building of the termites, on p. 352 

 of the wing-removing of Lipoptena; the accounts of mrymecophily on 

 p. 552, of the elaborate economy of solitary bees and wasps on pp. 490 and 

 510; and of the complex communal life of the social bees, wasps, and ants. 



With these or some of them well in mind the reader is ready to take 

 part in a consideration of some of the pertinent questions and problems 

 which such behavior, such long, highly coordinated series of actions, such 

 complex apparently psychic manifestations, inevitably bring up to the stu- 

 dent of animal life. On what sort or degree of organization of nervous 

 system does this complexity and high and effective coordination of behavior 

 depend? Is the behavior thoroughly adaptive? How rigid or invariable is 

 the behavior; that is, is there any apparent capacity to modify the behavior 

 to suit special cases or suddenly appearing new conditions? Is there any 

 element of reason, any intelligent choice of action, in the behavior? Or on 

 the other hand in how far can complex instincts be analyzed into simple 

 rigorous tropismic or reflex actions? 



There is space here to consider but one or two of these problems, and 

 we may select those which are perhaps of most interest. Let us select the 

 matter of the degree of rigorousness or invariability of behavior manifest in 

 insect instinct, and the matter of the possession by insects of any degree of 

 intelligence or reason; that is, the question of whether or not insect behavior 

 is exclusively reflexive and instinctive or is chiefly instinctive but tempered 

 by some degree of intelligence. 



This particular problem has been considered and discussed most per- 

 haps in connection with the elaborate and highly specialized behavior of the 

 solitary and social Hymenoptera (wasps, bees, and ants). And there are 

 strong champions for both points of view. Three observers and students of 

 insect life are preeminently conspicuous by virtue of their detailed and long 



