1897.] The Optic Lobes of the Bee’s Brain. 373 
through them ina direction nearly at right angles to their two 
surfaces. But such evidence is always fragmentary, and it is 
not until one employs the bichromate of silver method and 
thick sections that one is able to. find unbroken individual 
fibres passing thus from one side’to the other. Such fibers 
always show short arborescent branches in the outer and also 
in the inner lenticular mass. From the inner surface of the 
second fibrillar body they pass inward to the outer surface of 
the third body, which they enter, terminating arborescently a 
little below the surface. In this passage from one mass to the 
other they form, as seen in horizontal sections, a chiasma; so 
that a fiber emerging from the anterior side of the middle body 
enters on the posterior side of the inner body. 
In many instances cellular connections were seen with the 
fragments of fibers crossing the masses and presenting the short 
lateral branches mentioned. In such instances the impreg- 
nated cells were found in the groups of cells lying anteriorly 
and posteriorly near the fibrillar bodies (2, 2’, 2’’, 3, 3’, 3”). 
Their processes do not always enter the fibrillar bodies imme- 
diately upon reaching them, but run along the surface, curving 
around the fibers that do enter, and altogether presenting a 
somewhat lattice-like appearance when viewed at right angles 
to the surface of the body. 
From the inner mass such crossing fibers have frequently 
been readily traceable into the anterior tract going to the optic 
body, but not into the postero-superior tract, which I was 
obliged to make out in heavily impregnated specimens. 
From the outer surface of the middle body individual fibres 
have often been traceable nearly to the basement membrane of 
the retina, each posterior fiber crossing to the anterior side, 
forming with the anterior fibers the outer chiasma, and outside 
of this the peculiar palisade-like appearance that has been 
noted by the earlier authors. 
Such fibers terminate proximally in the outer Aecitioatar 
portion of the middle body in fine branchlets. Now and then 
a fiber entering this mass apparently from the palisade-like 
group of fibers gives off a few lateral branchlets and continues 
to the i ata side. Such cases I have interpreted to be the 
