142 Journal of Comparative Neurology. 



ganglia. The optic lobes and the suboesophageal ganglion are 

 part of it. There is no real ground for leaving the latter por- 

 tion out as is generally done under the term suboesophageal. 

 Even when it is widely separated from the larger mass and is to 

 be found crowded back into the pro-thorax, there is abundant 

 reason, as shown by the physiological experiments of Binet 

 (94) and others, for retainmg this portion under the general 

 term brain. Hence in subsequent pages it will be referred to 

 as the ventro-cerebron in contrast to the super-intestinal portion 

 6r dorso-cerebron. 



The optic lobes will be omiited from this paper for consid- 

 eration in a later one. 



The bee's brain thus limited is, roughly speaking, when 

 viewed from the front, a quadrilateral structure, with rounded 

 angles. Setting aside the ventro-cerebron, which projects back- 

 ward, it is considerably compressed antero-posteriorly (PI. XX), 

 and abuts closely against the middle upper portion of the pos- 

 terior walls of the head, leaving a very considerable space in 

 front filled with tracheal air-sacs and the whitish, often yellow- 

 ish or orange racemose bunches of the salivary glands. These 

 latter organs also fill in the smaller spaces behind the brain and 

 are closely applied to it. On the dorsal side are three small 

 protuberances (PI. XVII, XX) with black tops, or the so-called 

 ganglia of the ocelli. Below in the lower third the brain is 

 pierced by a large oval opening, the oesophageal foramen, with 

 its largest axis vertical. Near the roof of this is the longitu- 

 dinal median nerve of the stomatogastric system. On either side 

 and below the foramen are the rather conspicuous antennal 

 lobes forming the greater portion of what has been described as 

 the deuto-cerebron. The ventro-cerebron, as already mentioned, 

 projects considerably backwards, but it is so closely united with 

 the dorso-cerebron by extremely thick and short oesophageal 

 commissures that it is very readily recognized as part of the 

 brain. So compact is this deuto-trito-cerebral portion of the 

 brain that were it not for the fact that the labral nerves are rec- 

 ognized as arising from it, indications of the trito-cerebral lobe 



