ANTS AND SOME OTHER INSECTS. 21 



ence, memory and habit follow in the social insects on the whole 

 (the same fundamental laws as in the vertebrates and ourselves. 

 Furthermore, attention is surprisingly developed in insects, often 

 taking on an obsessional character and being difficult to divert. 



On the other hand, inherited automatism exhibits a colossal 

 preponderance. The above-mentioned faculties are manifested 

 only in an extremely feeble form beyond the confines of the in- 

 stinct-automatism stereotyped in the species. 



An insect is extraordinarily stupid and inadaptable to all things 

 not related to its instincts. Nevertheless I succeeded in teaching 

 a water-beetle (Dytiscus marginalis} which in nature feeds only in 

 the water, to eat on my table. While thus feeding, it always exe- 

 cuted a clumsy flexor-movement with its fore-legs which brought it 

 over on its back. The insect learned to keep on feeding while on 

 its back, but it would not dispense with this movement, which is 

 adapted to feeding in the water. On the other hand, it always at- 

 tempted to leap out of the water (no longer fleeing to the bottom 

 of the vessel) when I entered the room, and nibbled at the tip of 

 my finger in the most familiar manner. Now these are certainly 

 plastic variations of instinct. In a similar manner some large 

 Algerian ants which I transplanted to Zurich, learned during the 

 course of the summer months to close the entrance of their nest 

 with pellets of earth, because they were being persecuted and an- 

 noyed by our little Lasius niger. In Algiers I always saw the nest- 

 opening wide open. There are many similar examples which go 

 to show that these tiny animals can utilise some few of their expe- 

 riences even when this requires a departure from the usual in- 

 stincts. 



That ants, bees, and wasps are able to exchange communica- 

 tions that are understood, and that they do not merely titillate one 

 another with their antenna? as Bethe maintains, has been demon- 

 strated in so many hundred instances, that it is unnecessary to 

 waste many words on this subject. The observations of a single 

 predatory expedition of Polyergus, with a standing still of the whole 

 army and a seeking for the lost trail, is proof sufficient of the above 

 statement. But, of course, this is not language in the human sense ! 



