40 JOURNAL OF ENTOMOLOGY AND ZOOLOGY 
tral than that of the postantennal mass of cells. I was unable to 
detect any special lobe of the brain connected with this nerve. 
Branches from this trunk run dorsally and ventrally. Closely 
connected with this nerve on each side a little distance forward 
from the base of the brain is a small ganglion with a few nerve 
cells. These little centers I believe represent the paired vis- 
ceral ganglia of other insects. <A little cephalad of the level of 
these small nerve centers and dorsal to the esophagus, between 
the antennal nerves there is a minute ganglion with a number of 
little branches. This I believe is the frontal. From it on each 
side an arched nerve descends to connect with the two lateral 
ganglia just where they meet the labial nerve. Other branches 
go to the head region and one descends on the dorsal side of 
the intestine for some distance. 
In order to determine the position of various parts of the 
ganglia, there was made in blotting paper a model of the large 
head centers and this, together with a graphie reconstruction 
from a very perfect series of longitudinal sections, furnished 
the basis for most of Figs. 1 and 2. 
Somer GENERAL CONCLUSIONS 
(1) There are two large ganglia in the head, one for each 
segment of the thorax and a fused mass of nervous tissue in the 
upper abdominal region. 
(2) The abdominal ganglion is clearly made up of several 
centers fused together. 
(3) The supraesophageal ganglion has an antennal nerve on 
each side. There is also a labral nerve of smaller size and a 
connection on each side with the postantennal sense cells. 
(4) The subesophageal ganglion is joined by broad con- 
nectives with the brain and by less broad connections with the 
first thoracic ganglion. ; 
(5) There are three main nerves connected with the sub- 
esophageal ganglion—the mandibular, maxillary and labial. 
(6) Connected with the brain are three small ganglia, the 
frontal and two lateral visceral ganglia. The first of these is 
very small. 
