246 Annals Entomological Society of America [Vol. IV, 



Finally the tritocerebrum is well marked as a little lobe just 

 dorsal of the crus giving off the rather large clypeo-labial 

 trunk which with the arched nerve comes off as one. From the 

 distribution of this it seems probable that it is mixed. 



This arched nerve runs ventrally and cephalad to unite at 

 the middle line with the one of the opposite side in the frontal 

 nerve ganglion. A branch from this small nerve center runs for- 

 ward as the frontal nerve, another runs back on the dorsal 

 surface of the esophagus to the small vagus ganglion, which 

 sends two branches farther down the alimentary canal. 



General form, of the Brain from Methylene blue. 



In successfully stained preparations almost all parts of the 

 brain, especially the parts in from the nerve trunks are seen to 

 be covered with nerve cells, both large and small. Those just 

 under the chitin seem to quite completely incase the central 

 dark staining portions of the ganglion. This central dark mass 

 in each well separated lateral half of the ganglion is roughly of 

 the same general shape as the surface. In the main part out 

 from the median portion there is a lobe deep in and opposite the 

 ocular nerve, this is in the central portion of the ganglion and 

 connected with it, but extending down into the tritocerebrum is 

 another lobe almost as large near the crus. 



Partly separated from the central lobe of " punktsubstanz " is 

 a spherical mass of dark staining substance and out from this a 

 little distance in the ocular lobe and beyond its constriction 

 from the main part of the protocerebrum is another little mass 

 of deeply colored material. About each of these last little 

 masses of " punktsubstanz " a special arrangement of cells is seen, 

 while over the surface of the main portion of dark substance on 

 every side the cells form a thick covering. 



Fibers running up the crura may be traced into the ganglion 

 in its dorso-caudal region. Some apparently run only to the 

 lower portion of the "punktsubstanz," others may be followed 

 farther up and are lost in the central area. Fibers can also be 

 traced to the central portion of the ganglion, to the medial 

 portions and probably freely ramify all through the central 

 mass. 



Near the middle line of the ganglion some large cells on the 

 surface were found with long processes extending down long 

 distances in the direction of the crura and probably were con- 

 tinued into it. 



