PHOTIC REACTIONS OF HONEY-BEE 



353 



The illumination of the apparatus resembled the semi-indirect 

 illumination of a modern house, the light from an incandescent 

 lamp being diffused through a circular screen (fig. 2, s), 22 cm. in 

 diameter, of white bond paper. Two intensities of illumination 

 were employed. The less intense was produced by a carbon 

 filament lamp of approximately 2 c.p.,^ 66 cm. above the floor, 

 and the more intense by the 80 c.p. mazda lamp previously 

 described, 33 cm. above the floor. The intensity of illumination 

 in each instance was measured at three different points on the 

 floor of the cylinder. One determination was made at the cen- 

 ter; a second at a point 3 cm. from the right side wall, and a third, 

 at a point 3 cm. from the left side wall. The results of these 

 measurements are given in table 1. Hereafter, in referring to the 



TABLE 1 



two intensities of illumination employed, the averages given in the 

 table will be used in round numbers. The less intense will be 

 designated as non-directive light of 24 mc. ; the more intense, as 

 non-directive light of 957 mc. 



The transference of bees to and from the apparatus was effected 

 by means of a small, cylindrical cage of wire screen, 5 cm. in 

 length by 2 cm. in diameter (fig. 2, c). This cage, one end of 

 which was open, exactly fitted into a circular opening cut through 

 the table top to the center of the chamber floor. By means of a 



* The lamp used throughout experimentation was, unfortunately, broken 

 before being determined photometrically. Its candle-power was certainly 

 between 2 and 4. 



* Throughout the present paper, the abbreviation mc. will be used to designate 

 meter candles. 



