144 Journal of Comparative Neurology. 



tion, however, I infer them to be the mandibular, maxillary, 

 and labial nerves. From the posterior lower surface of the 

 ventro-cerebron there arises a small seventh pair of nerves di- 

 rected backwards and downward toward the region just below 

 the foramen magnum. Just how they terminate or what their 

 function may be I have not thus far been able to determine. 

 They were seen by Viallanes (s?) in the wasp, but were left as 

 now still to be traced. 



In his monograph on the brain of the Orthoptera, Viallanes 

 (88) described under the name of " nerfes tegumentaires " a 

 pair of nerves emerging from the surface of the brain and pass- 

 ing on to the roof of the head. These appear to be nothing 

 more nor less than a pair of nerves that he found in the wasp 

 the year before and described as nerves of unknown termina- 

 tions. 



This eighth pair of nerves is readily seen and traced in the 

 bee and one may be recognized in section in the lower photo- 

 graph in plate XVI. Both in bichromate of silver and in hsema- 

 toxylin preparations I have been able to trace out its entire 

 course and to show that Viallanes' denomination of tegument- 

 ary nerve is entirely a misnomer. It arises from the side of the 

 ventro-cerebron where its root enters the latter, passes in, some- 

 what downwards and backwards, towards the median line of the 

 latter, makes a turn backwards and becomes lost in the general 

 mass of fibrillar substance. The nerve (PI. XVII) closely adher- 

 ing to the posterior surface of the brain and beneath the gen- 

 eral envelope of the latter passes outwards and upwards until i-t 

 reaches the upper portion of the posterior surface of the inner 

 or third optic fibrillar mass or ganglion, where it branches. One 

 branch continues almost perpendicularly upwards, passes out of 

 the brain envelope and branches among the lobes of the saliv- 

 ary glands. In bichromate of silver preparations the branches 

 may be followed into the lobes, but I have not yet seen the 

 finer terminations. The other large branch continues outward 

 along the supero-posterior surface of the optic lobe, branching 

 and leaving the envelope from time to time, and may be fol- 

 lowed to the basement membrane of the retina where it finally 



