250 Annals Entomological Society of America [Vol. IV, 



dorsal side of the brain. This runs down to the mid-ventral 

 line and there branches into two parts, one ventral, the other 

 dorso-lateral. Farther along each of these parts run caudally 

 as a single piece, one ventrally, the other dorso-laterally and 

 the middle portion of the rod and afterwards the dorsal part 

 disappears in section because of the curve in it. Later the 

 lateral part disappears and the mid-ventral portion extends in 

 towards the middle line to meet, but not unite with its fellow of 

 the opposite side, running caudally in this way some distance, 

 just above a ventral fibrous commissure and below a broad 

 central one. In other words this body is a long slightly curved 

 rod standing up in the ganglion with its base divided into two 

 portions of which the lateral is shorter, the median longer 

 and extends in towards the middle line. These represent the 

 stalks and roots of the "mushroom bodies," the cup, such as 

 described by Kenyon and others is not present and the special 

 cells if developed were not recognized. This stalk and root of 

 fibrous substance seemed to have a lighter core, that is in sec- 

 tions it gave to some extent the appearance of a tube. The 

 fibers which compose it are very densely massed together. 

 Preparations in which the tissues were allowed to macerate 

 showed them to be little affected. 



On the cephalic margin of the brain as on the dorsal side, 

 the central fibrous mass as a whole is lobed as already spoken of 

 and masses of cells fill in over these. The cell groups are 

 difficult to describe in detail. The whole dorsal and lateral 

 portions of the ganglia are covered with them, both large and 

 small and in places many cells deep. There are almost no cells 

 on the ventral side of the brain. 



Beginning laterally and dorsally we have about the spherical 

 mass of fibers back from the ocular lobes, masses of cells, on 

 the dorsal, ventral and mesal sides. A peculiar condition of some 

 of the dorsal and ventral sides of this mass is the appraent epi- 

 thelial character of some of the cells. Most of these are very 

 small and are probably neuroblasts. The epithelial character 

 is especially marked in two places on each side because there 

 are little cavities one dorsal and one ventral in the outer por- 

 tion of the circular mass of fibers. (Plate XV, Figs. 1, 2, 3.) 

 There are some fibers from the two lateral groups of cells just 

 described which run both to the mesal group and out the ocu- 

 lar nerve. This is also continued dorsally and forms all along 



