146 C. H. TURNER. 



would often return to the maze, roam around and then remount 

 the incline. With a few exceptions, the caterpillar finally reached 

 the table and departed. In a few cases it reascended the incline 

 after reaching the table, and in yet fewer cases the caterpillar 

 finally rested indefinitely upon some portion of the maze. 



In spite of the individuality, there were four things common to 

 the behavior of all of the caterpillars placed on the horizontal 

 maze, (i) The caterpillars usually traveled along the edges of 

 the maze, instead of along the middle of the roadway. (2) At 

 frequent intervals the creature would stop, cling to the maze 

 with its prolegs, stretch the front part of the body forwards and 

 dorsalwards and wave it about in a wabbly manner. (3) On 

 reaching the incline for the first time, it practically invariably 

 moved upwards. (4) In all cases the locomotions were random 

 movements. Any interpretation of the behavior on the maze 

 must be in harmony with these four factors. The first and the 

 third are the only ones suggesting that the reactions of these 

 caterpillars are tropisms. The almost constant clinging to the 

 edges of the maze suggests some form of a positive thigmotro- 

 pism; the invariable ascension of' the incline upon its first en- 

 counter seems to predicate a negative geotropism. 



If the clinging to the edges of the maze is indicative of a posi- 

 tive thigmotropism, why does not the caterpillar show a pro- 

 nounced tendency to linger in the many angles of the vertical 

 maze? Why does it not rest indefinitely in the angle between 

 the upper portion of the cardboard incline and that alley of the 

 horizontal maze upon which it rests? Would it not be more 

 consistent to believe that the caterpillars move along the edge 

 because they secure a better foothold there than upon the smooth 

 surface of the copper maze? 



The fact that the incline was invariably ascended when first 

 encountered requires critical analysis. An examination of the 

 notes made at the time of the experiments shows that whenever 

 the caterpillar upon the maze came in contact with the incline 

 its head was directed towards its upper edge. A thoughtful 

 consideration of the physical conditions of the horizontal maze 

 used and of the normal movements of a caterpillar on the maze 

 shows that such a condition is inevitable. Should a caterpillar 



