362 DWIGHT E. MINNICH 



against the glass. Or, if escaping in a darkened room, they not 

 infrequently flew directly into the flame of the nearest gas jet. 



Observations of this sort were long ago reported by Lubbock 

 ('82, pp. 278, 279, 284). A few years later, Graber ('84) demon- 

 strated the same thing experimentally by confining forty to sixty 

 bees in a small box, one half of which was illuminated by direct 

 sunhght, the other half being shaded, with the result that the 

 majority of the bees soon collected in the illuminated end. More 

 recently, Hess ('13 a, '13 b, '17) has repeated this and a variety 

 of other experiments. As a result of these he has been able to 

 show that in the presence of several sources of photic stimulation, 

 which differ in color and intensity, bees always orient toward 

 the one which to a totally color-blind person appears brightest. 

 The positive phototropism of the honey-bee is thus demonstrable 

 in a variety of ways. 



In the experiments just cited, winged bees were used exclu- 

 sively. My own experiments, on the contrary, were confined en- 

 tirely to workers from which the wings had been clipped. Such 

 bees when creeping in the directive light area exhibited an orien- 

 tation which was striking in three respects, viz., its rapidity, its 

 precision, and its constancy. 



An individual to be tested was removed from the dark box and 

 exposed to light for a few minutes until it was thoroughly active. 

 It was then allowed to creep from its screen cage to a small, 

 rectangular piece of black paper, and on this it was transferred to 

 the edge of the directive light area. An effort was made to start 

 the animal creeping at a right angle to the direction of the hght 

 rays by turning the paper just before it crept off. The rapidity 

 of orientation was so great, however, that the intervening centi- 

 meter or so was frequently sufficient to allow the animal to reorient 

 perfectly. Since the velocity at which bees creep averages 3 to 6 

 cm. per second, orientation in these cases occurred in considera- 

 bly less than one second. I have also tried leading a bee by 

 moving the light, now in this direction, now in that, with varying 

 degrees of curvature. Always the animal followed, orienting rap- 

 idly to even slight movements of the lamp. 



