Tropisms in Insect Behavior 23 



dently it was not darkness as such that it refused to en- 

 ter, but darkness associated with a peculiar kind of floor. 

 It was responding to a darkness that had acquired a 

 meaning; it was responding to darkness, not as a con- 

 troller of tropism, but to darkness as a perception. If 

 you have any doubts as to the soundness of your analysis 

 place the roach on an open maze so arranged that to fall 

 from the runways means a plunge into cold water. In a 

 reasonably short time the roach will learn to run the 

 maze, although in doing so it crosses the rays of light at 

 several different angles.' 



Several kinds of insects — bees, wasps, ants, flies — have 

 tlie habit of hovering in great swarms and performing 

 what looks like a sun dance. In the case of certain flies, 

 at least, all seem to be facing the wind and the behavior 

 has been interpreted as an anaemotropism. Examine the 

 hovering swarm carefully — be it composed of bees, 

 wasps, ants or flies — and you will find that the partici- 

 pants are males. Occasionally a female corkscrews 

 through the group or approaches its outskirts. Im- 

 mediately a few males dart in pursuit and the rest go on 

 with the dance.* Evidently this is a prenuptial dance 

 and is probably no more of an anaemotropism than is the 

 soaring of a vulture. When we remember that the hover- 

 ing of some flies consists in hovering before a wall or 

 other opaque body this point of view is strengthened be- 

 cause such a fly cannot be facing the wind, since the wind 



* Turner, C. H.; Behavior of the Common Roach (Periplaneta ori- 

 entalis) on an Open Maze. Biol. Bull., Vol. XXV, 1913, pp. 348-365. 



•Turner, C. H.; The Sun-Dance of Mellissodes. Psyche, 1909. 

 Turner, C. H.; The Mating of Lasius. Jour, of Animal Behavior, 

 Vol. V, 1915, pp. 337-340. 



Rau, Phil and Nellie; Wasp Studies Afield, 1918, pp. 9-17. 



P6rez, J. — Sur Quelques Particularit6s Curieuses du Rapproache- 

 ment des Sexes chez Certains Deplores. Bull. Scientifique de la France 

 et la Belgique. 1911, 7th series, T. XLV, pp. 1-14. 



