104 
EYES AND SIGHT. 
experiment is repeated and the crystalline cones are 
left in situ., the field of view appears perfectly black, 
with a bright spot of light at the end of each cone, 
and no trace of an image can be perceived, showing 
that the images of Leeuwenhoek are thrown by the 
cornea only. Lowne contends for Muller’s theory, 
which is the one now generally accepted. 
Besides the faceted eyes, bees have on the upper 
part of the head three simple eyes. Their disposition 
in the different sexes has been described in Chap. IV. 
(Fig. 7). They are called stemmata, or ocelli., but it is 
hardly correct to call them simple eyes, for their struc- 
ture, as J.eydig (95), who has studied them, points 
out, resembles very much that of the compound 
eyes. The cornea is very convex, and the crystalline 
cone, or lens, fits into a cup-shaped cavity, behind 
which are found structures similar to those de- 
scribed in the compound eyes. The eyes are similar, 
and the cornea and the crystalline lens have each 
become separately fused, while the rods which remain 
separate are brought close together. The ocelli are 
connected by nerves to the upper part of the brain 
and convolutions (pedunculated bodies of Dujardin, 
page 68). Each side of the brain sends nerves to 
the simple eye situated on the same side, the centre 
one receiving its nerves from the right and left sides. 
What, therefore, is the function of these different 
forms of eyes ? 
Our knowledge with regard to practical vision in 
bees is still very imperfect, although no one will 
deny that sight is highly developed. Lowne has caL 
