220 PRINCIPLES AND CONCLUSIONS. 



"I hope to prove that any mystic or mysterious theory of special sense, sixth sense, 

 magnetism, etc., is as superfluous as false for the whole animal series. The known senses, 

 their variations, and the memories which are derived from them explain everything" 

 (p. 196). 



As a result of experiments of his own (1895; cf. Rau, 1918:278), Weis- 

 mann concluded also that "the only correct solution of the enigma of 

 path-finding by Chalicodoma is that the insects find their way back with 

 their eyes." (See also Perez, 1895.) 



Homing faculty of bees. — Romanes (1885:630) conducted observations 

 to determine whether honey-bees find their way home by means of land- 

 marks or by means of a mysterious sense. A hive of bees was placed in a 

 basement room of a house situated several hundred yards from the coast, 

 with flower gardens on each side and lawns between the house and the sea. 

 A definite number of bees was used in each experiment and those that 

 returned were caught by means of birdlime. The first score of individuals 

 were taken out to sea, whence none of them returned; the second lot was 

 liberated on the shore, but none returned. The same result was obtained 

 when the next lot was released on the lawn between the shore and the 

 house, although the distance to the hive was not over 200 yards. Finally, 

 when bees were freed in different parts of the garden, they were always 

 found stuck in the birdlime within a few minutes, often arriving before 

 the observer could reach the hive. As the garden was a large one, many 

 of these bees had to fly a longer distance than those released on the lawn 

 and their uniform success in reaching home quickly was due to their special 

 knowledge of the garden. The results convinced Romanes that bees de- 

 pend entirely upon their special knowledge of a district or landmarks and 

 not upon any general sense of direction. 



Sense of direction in ground-wasps. — The Peckhams (1887:113) 

 performed a number of experiments to determine whether wasps possess 

 a mysterious sense that enables them to fly in a straight line to any desired 

 point, even though they have never been over the fine before. When 63 

 workers were carried 200 yards west to the top of a hill in sight of the nest 

 and 10 released, they flew off in all directions, not taking the east toward 

 the nest oftener than the other directions. Three, after circling about, 

 settled again on the stump, but after some hesitation started off. When 

 20 wasps, 10 of which were marked, were set free on a lake, nearly all 

 flew in the direction of the wind, toward the nest, but in the next test 

 with 26 individuals, 6 took a direction opposite to that of the nest, 10 

 returned to the boat and seemed loath to leave, while several seemed to 

 change their minds and altered their courses. Two days later 32 wasps 

 were released on the lake a half-mile north of the nest; 8 of these returned 

 to the boat, some of them twice, 6 or 7 flew in a straight fine against the 

 wind and over the lake to the nest, while 17 or 18 flew toward the shore. 

 A second group of 40 was released, to fly in all directions, but most of them 

 returned to the boat. Of the 135 wasps set free, it seemed fairly certain 

 that they did not fly toward their nest as frequently as in an opposite 

 direction. It also appeared that they were at a loss to know which way to 

 go, since they often returned once or twice for a new start. Of 55 wasps 

 released in a later experiment, 39 returned to the nest in about an hour's 

 time. When 38 workers were set free in a room with opposite windows, 



