244 Annals Entomological Society of America [Vol. IV, 



Maxillary. Fibers were followed into this from the lower 

 connectives and from the upper parts of the ganglion. From 

 this nerve trunk some fibers seem to end near the junction of 

 the nerve with the central "punkstubstanz." 



Labial. This is made up from fibers which enter the ven- 

 tral central portions of the ganglion, just above the entrance of 

 the small ventral nerves. They may be traced from the con- 

 nectives up and from the upper portion of the ganglion down 

 into these trunks and ventral caudal cells evidently contribute 

 fibers to the mingled mass which is connected with these 

 branches. 



(d) Commissures. 



The commissures connecting the crura cerebri have fibers 

 which cross from one side to the other in the case of descending 

 or ascending strands. No other kinds were recognized although I 

 think there is a strong probability that some fibers merely 

 cross and do not descend at all. 



Within the ganglion there are a number of commissures 

 connecting the lateral halves. Some of these are of straight 

 fibers, others are closely woven deep staining masses. Dorsal, 

 ventral or median commissures are found at almost every level, 

 especially ventral ones, although not always clearly marked. 

 A longitudinal section through the whole ganglion shows from 

 three to four main commissures, a cephalic, a caudal and two' 

 median ones. 



THE SUPRAESOPHAGEAL GANGLION. 



(Figs. 8, 9, and PI. XVI, Figs. 1-4.) 



The brain is made up of two large ovoid masses distinctly 

 marked from each other on the the middle line. It is connected 

 on the ventral side to the subesophageal ganglion by means of 

 the short, broad crura cerebri. All of the larger nerves come 

 out laterally and of these there are three main trunks, the only 

 ones to be considered at this time. 



Three portions of the brain may be made out each con- 

 nected with these trunks. The most dorsal is the protocere- 

 brum, and it is also the largest and best marked and connected 

 with the optic nerves which divide on each side into seven 

 branches one for each ocellus. 



