254 Annals Entomological Society of America [Vol. IV, 



often well marked mid-dorsal masses of large and smaller cells, 

 as well as scattered cells in all parts. In the more cephalic 

 ganglia, the cells are not quite the same in distribution. Cell 

 groups and masses are found abundantly ventrally, but also on 

 the dorsal and lateral sides and also great masses of them at the 

 cephalic as well as the caudal end. 



In the supra esophageal ganglion, cells are especially abun- 

 dant dorsally and on the cephalic and caudal borders, less abun- 

 dant laterally and ventrally. The cells are very numerous. 

 Each side of the middle line a group was located with very 

 long processes, the cells being mostly large. 



Other groups were densely massed lateral to these, both 

 cephalad and caudally, some of them were large, others small, 

 and two groups of small cells on each side out near the optic 

 nerves were found with a cavity near them. 



Nerve cells were found partly surrounding two masses of 

 fibers on each side near the optic nerves. 



From the distribution of the cells and fibers there was no 

 evidence of the dorsal cells being especially motor and of 

 a ventral, particularly sensory region as Binet was led to 

 think from experiments. I would rather incline to Kenyon's 

 idea of ventral motor and dorsal sensory if I choose either of 

 the two views, as undoubtedly most of the ventral cells in the 

 thoracic and abdominal ganglia are motor cells, while many if 

 not most of the fewer dorsal cells of these ganglia seem to be 

 association cells, sending their fibers superficially over the sur- 

 face or deeply into and through the fibrous mass to be associated 

 with the cells and fibers of the ventral side. 



7. In all of the ganglia the central mass into which many 

 of the nerve cells send their processes has a very complex ar- 

 rangement of fibers and nerve terminations. Certain portions 

 of this mass in all are much denser than the rest. 



In the brain this central "punktsubstanz" is somewhat 

 more intricate in its texture on the dorsal side than on the 

 ventral and is more or less lobed while off from the central mass 

 there are two smaller groups of "punktsubstanz" in connection 

 with the optic nerves on each side. In the central part of the 

 brain is a stalk and root of a mushroom body on either side, but 

 the cup is not present. The ventral portion of the ganglion is 

 mostly made up of straight fibers. 



In all of the lower ganglia there are at almost any level, 

 from one to three commissures recognizable, a dorsal, a median 



