SENSES OF BEES. 315 



after dusk in the evening, are obliged to lie abroad 

 all night. The same peculiarity, added to the 

 acuteness of their smell, has given birth to various 

 contrivances for inducing bees of different hives 

 to mingle peaceably together, as mentioned at 

 page 154. 



From the experiments of Swammerdam, Reau- 

 mur, Hooke and others, it seems that bees and other 

 insects, particularly those of the hymenopterous 

 order, possess organs of vision, besides those which 

 are properly called their eyes. These organs, 

 known by the name of STEMMATA, are three smooth, 

 glossy, hemispherical dots, placed in a triangular 

 position upon the vertex or top of the head. The 

 two reticular eyes of one of these insects having 

 been covered with fluid pitch, (the stemmata being 

 left open,) when placed under a glass, the insect 

 ran up and down, but without striking against the 

 sides of the glass. In a similar experiment upon 

 a dragon-fly (Libellula), the insect flew away, 

 but in its flight struck against walls and other 

 objects. The stemmata in another insect being 

 covered, and the reticular eyes left open, seemed 

 to cause no impediment to its usual proceedings, 

 \h appeared to see as well as before. But when 

 |both the stemmata and the eyes were covered, 

 |the insect seemed to be totally deprived of sight, 

 |it walked slowly under the glass, and when allowed 



