THE 
AMERICAN NATURALIST 
VoL. XXXI. May, 1897. 365 
THE OPTIC LOBES OF THE BEE’S BRAIN IN THE 
LIGHT OF RECENT NEUROLOGICAL METHODS. 
By F. C. KENYON, 
WASHINGTON, D. C. 
While studying the central mass of the brain of the common 
honey bee, which I have already described with some detail, 
there was abundant opportunity offered for noting the finer 
structure of the so-called optic lobes. From the casual obser- 
vations then made I take the following notes. 
The general form of the optic lobes, as well as the cellular 
and fibrillar masses composing them, have been fairly well de- 
scribed by Berger, Viallanes and others for other hexapods, 
and what one finds in the bee does not differ materially from 
these early descriptions, so far as the inner two fibrillar masses » 
are concerned (f.m.2 and 3). In the bee I note that there are 
three of these fibrillar masses, all easily recognized in frontal, 
but less so in horizontal sections (f. m. 1). The outer mass 
presents a lunar appearance in frontal sections, and lies close 
inside the basement membrane of the retina, being separated 
from it by sufficient space for the entrance of large tracheal 
sacs and a thin layer of cells commingled with the fibers from 
the retina. 
1 The Pi of the Bee. Journ. Comp. Neurology. Vol. VI. Fase. 3, 1896. 
pp. 133-21 
