Ken YON, The Brain of the Bee. 145 



emerges to pass into the glandular lobes situated in proximity 

 to that structure. The nerve, then, instead of having anything 

 to do with the integument, is the nerve to the salivary glands, 

 and is doubtless made up entirely of efferent fibres. 



The small pair of nerves described by Newton ( 79) as 

 arising from the anterior surface of the brain in Blatta and go- 

 ing to the small white spot near the base of each antenna, 

 are not, so far as I have been able to discover, represented in 

 the bee. 



THE GENERAL INTERNAL STRUCTURE. 



Internally the brain is composed of a mass of very fine 

 fibrils scarcely recognizable as such in ordinary preparations, 

 which is very well called fibrillar substance. The upper portions 

 of the anterior surface of this below the mushroom bodies to 

 be described later and the corresponding part of the posterior 

 portion of each of the two lateral lobes are directly covered by 

 the membrane forming the perineurium. But in the region of 

 the mushroom bodies, laterally, in the posterior median furrow, 

 and below, about the greater part of the antennal lobes, fill- 

 ing the space between these and the proto- cerebron, and the 

 lower and lateral surface of the ventro-cerebron (the upper sur- 

 face of the latter is bare) it is covered by heaps of cells which 

 spread out into layers of only one or two cells deep. Processes 

 from many of these cells are gathered into large bundles which, 

 penetrating the fibrillar substance, give it — both the brain and 

 the ventral system as seen in sections — a lobular appearance that 

 has been the subject of no inconsiderable amount of painstak- 

 ing and lengthy and as tedious description, notably by Vial- 

 lanes, and later by Binet (94) in his paper on the sub-intestinal 

 nervous system of insects. The fibers thus entering become 

 lost in the fibrillar substance by repeated branching or continue 

 first to more distant parts, thus forming connecting tracts. This 

 relation of the fibrillar substance and the fibers may be readily 

 seen in the accompanying photographs, and in most prepara- 

 tions by ordinary staining methods. The assistance of the 

 method of impregnation with bichromate of silver or that of 



