Ken YON, The Brain of the Bee. 183 



arched slightly upward. It may be followed with little difficul- 

 ty in ordinary preparations, and I have several times found its 

 fibers impregnated in brains treated by the bichromate of silver 

 method. Whether its fibers branch in the central brain I can- 

 not say definitely. There are indications, however, that they 

 do, and further, that their cells of origin may be situated among 

 those forming the mass of cells behind the central body. 



Below this, in a plane taking in the anterior optic tracts 

 and the optic body, and a little below the lower level of the in- 

 ner roots of the mushroom bodies, there are three tracts, which 

 may be seen in figure 10, PI. XVI. These differ considerably 

 according to the direction of the plane in which the section is 

 cut, and also seem to differ somewhat in different individuals. In 

 another brain from that from which the figure was taken there is 

 a bundle that is not shown in the figure. This is described by 

 Viallanes ( S7) as divided into a thicker and a thinner bundle, 

 which is the case here. Both emerge from the inner edge of 

 the inner lenticular body and terminate in the neighboring cen- 

 tral region after penetrating no further than do the posterior two 

 of those shown in the figure. The anterior of the two is con- 

 siderably the larger and from its manner of staining may readi- 

 ly be considered as composed of many very fine fibrils. The 

 other is composed of fewer and coarser fibers and seems to 

 arise more directly from the space between the two lenticular 

 bodies. 



Below these are two more bundles, or the posterior two 

 shown in the figure. These resemble the one just described 

 and arise and terminate similarly. 



At a slightly lower level is the last of the series, which 

 arises from near the margin of the inner lenticular body and 

 passing directly into the central mass, bends slightly down- 

 ward and then upward again to its former level and passes 

 on as the lower optic commissure to the lobe of the opposite 

 side. This is a much more compact and well marked bundle 

 than the upper optic commissure and seemingly gives off no 

 branches, although further study will probably show that it 

 does. In one preparation by the copper-hasmatoxylin 



