20 ANTS AND SOME OTHER INSECTS. 



observed. That this cannot be due to smelling at long range can 

 be demonstrated in another manner, for the olfactory powers of the 

 genus Formica, like those of honey-bees, are not sufficiently acute 

 for this purpose, as has been shown in innumerable experiments by 

 all connoisseurs of these animals. Certain ants can recognise friends 

 even after the expiration of months. In ants and bees there are 

 very complex combinations and mixtures of odors, which Von But- 

 tel has very aptly distinguished as nest-odor, colony- (family-) odor, 

 and individual odor. In ants we have in addition a species-odor, 

 while the queen-odor does not play the same role as among bees. 



It follows from these and many other considerations that the 

 social Hymenoptera can store up in their brains visual images and 

 topochemical odor-images and combine these to form perceptions 

 or something of a similar nature, and that they can associate such 

 perceptions, even those of different senses, especially sight, odor, 

 and taste, with one another and thereby acquire spatial images. 



Huber as well as Von Buttel, Wasmann, and myself have 

 always found that these animals, through frequent repetition of an 

 activity, journey, etc., gain in the certainty and rapidity of the ex- 

 ecution of their instincts. Hence they form, very rapidly to be 

 sure, habits. Von Buttel gives splendid examples of these in the 

 robber-bees, i. e., in some of the common honey-bees that have 

 acquired the habit of stealing the honey from the hives of strangers. 

 At first the robbers display some hesitation, though later they be- 

 come more and more impudent. But he who uses the term habit, 

 must imply secondary automatism and a pre-existing plastic adapt- 

 ability. Von Buttel adduces an admirable proof of this whole mat- 

 ter and at the same time one of the clearest and simplest refuta- 

 tions of Bethe's innumerable blunders, when he shows that bees 

 that have never flown from the hive, even though they may be 

 older than others that have already flown, are unable to find their 

 way back even from a distance of a few meters, when they are un- 

 able to see the hive, whereas old bees know the whole environ- 

 ment, often to a distance of six or seven kilometers. 



It results, therefore, from the unanimous observations of all 

 the connoisseurs that sensation, perception, and association, infer- 



