676 



THE AMERICAN NATURALIST [Vol. XLV 



ported in front of a fully opened cotton blossom pinned 

 in position. The surrounding cotton leaves were then 

 carefully drawn in closely around the plate so as to over- 

 lap the edges and most of the glass surface. In this 

 arrangement, although the blossom was plainly visible 

 through the glass, only a small portion of the glass sur- 

 face remained in view. 



At (b) control. A fully opened cotton blossom was 

 pinned in position. 



Data foe Experiment No. 30 





1 















I 



1 

 1 



& 



1 



! 



I 



I 

 1 





§ 



I 



j 



I 

 1 



I 



t 



i i. 

 i li 



s\ s 





18 





















4 



Of those bees which attempted to inspect the blossom 

 at (a), eight flew more or less forcibly against the glass, 

 including two small unidentified bees, one Bombus sp., 

 two honey bees and three Melissodes. One small bee 

 tried persistently several times to fly through the glass 

 toward the blossom just behind it. It is at once obvious 

 that the blossom at (a) invited inspection by passing bees 

 solely through the sense of sight. 



Experiment No. 31. — August 9. Observations con- 

 tinued one hour, from 9 :00 to 10 :00 a.m. 



Two blossoms were used in the same row as before. A 

 box of thin wood was carefully constructed for this 

 experiment. The dimensions were such that both cover 

 and bottom were made of thin clear glass by using for 

 each a 5x7 glass plate. These plates fitted tightly in 

 lateral grooves. The box was about 4 inches deep, so 

 that the end of a cotton branch together with its leaves 

 and blossoms could be carefully pushed into a natural 

 position within. By sliding the glass cover into place 

 the box became practically air-tight. The blossom was 

 plainly visible to passing bees, although any attractive 



