232 PRINCIPLES AND CONCLUSIONS. 



their position on the tarsi and the sting casts grave doubt upon their effec- 

 tiveness as olfactory pores. Their localization on the bases of the wings, 

 the legs, and the sting suggests that they have to do with the sense of touch 

 or feel in the wide sense and that their response to chemical stimuli is 

 somewhat similar to that of all exposed nerve-ends * However, it is idle to 

 speculate upon this until the results of new investigations, which take 

 into account the experiments of both Mclndoo and his predecessors, are 

 made available. 



Turner (1916:385) states: "These experiments of Mclndoo are pains- 

 taking and his anatomical studies of what he calls olfactory pores are 

 excellent, but the serious student, who is acquainted with the experiments 

 of Forel and others who 'claim that the antennae are the organs of smell' 

 will not be convinced that the last word has been said on the subject. 

 They do not seem to have met the criticisms raised by Forel" (1878, 1886, 

 1908), as indicated above. 



INTELLIGENCE. 



Relation between the senses and mental faculties of insects. — 



Forel (1886:233) considered that insects possess our five senses, with the 

 possible exception of hearing, in a well-differentiated degree and with a 

 special energy that we consider analogous to our own. The quality of their 

 vision is different from that of ours in certain respects, as certain of them 

 see the ultra-violet rays. Many insects have besides a kind of odor by 

 contact, which enables the ants in particular to distinguish their companions 

 from enemies. The development of each sense and of each of its kinds of 

 special energy (color, odor) varies enormously, not only for families and 

 genera, but even with related species and with the sexes of the same species. 

 Insects naturally combine their different senses in their acts, but in general 

 the principal sense is that of direction, just as sight is with man. Sight 

 assumes this role with the aerial insects, especially the dragon-flies and the 

 butterflies. With the workers among ants, it is in general smell, with the 

 spiders, touch, and with the beetles it is touch and taste combined. 



It is evident that insects possess the faculty of the so-called voluntary 

 movements which are not merely reflex or simply automatic, but very 

 well coordinated and nearly all dictated by combinations of instinctive 

 reason with the aid of sensory impressions, and admirably adapted to their 

 end. They frequently have an excellent memory of places, of things, and 

 perhaps of persons. Thus, insects reason, and the most intelligent of them, 

 the social Hymenoptera, reason much more than one thinks when he ob- 

 serves the mechanism due to instinct, but to properly observe and compre- 

 hend these reasoning processes, it is necessary to put instinct out of com- 

 mission. Instinct is organized, systematized, and automatic reasoning, 

 that is, it has become unconscious. Instinct and reason are not in inverse 

 proportion to each other, as Pouchet has remarked, and the insects with the 

 most intelligence are generally those with the largest number of varied 

 instincts, though this is not always true. Finally, insects exhibit passions 

 that are more or less bound up with their instincts, and these vary enor- 



* Since this was written, it has been found that Graber ascribed the sensitiveness of the 

 "afterborsten " and the legs to relatively strong odors to the sense of feel and not to that of 

 smell. 



