BRAIN OF THE 'WHITE ANT' 563 



The insect brain froms a ring of nerve tissue which encircles 

 the esophagus and which is composed of the supraesophageal gan- 

 glion,, the ventral connectives, and the subesophageal ganglion. 



The three parts of the supraesophageal ganglion, the proto- 

 cerebrum, the deutocerebrum, and the tritocerebrum, are merged 

 into a single mass which constitutes the principal part of the 

 brain. To the protocerebrum belong the protocerebral lobes, 

 p.L, the optic lobes, o.L, connected by the fibers of the optic 



/(J .^=^ / 



tn b. 



P.l. 

 """ -^ -^ 



ol 





t r.cm.\,...jz:;Xl >^. '/fQ'^ 



md.n 



sb. 



^■c. 'ifn. 



mx.n 



Ib.n. 



Fig. 2 Diagram of the brain of a nymph with long wing pads, as if seen in 

 frontal optical section. A.I., antennary lobe;/.f7., frontal gland; /.«.. fontanel 

 ncrvo; fr.gn., frontal ganglion: If.n., abrofrontal nerve; Ib.n., labial nerve; m.b., 

 mushroom body; ni'Z.n., mandibular nerve; mx.n., maxillary nerve; or. n., oc liar 

 nerve; o.L, optic lobe; p.'., protocerebral lobe; sb.g., subesophageal ganglion; 

 tr.cm., tritocerebral commissure; v.c, ventral connective. 



nerves with the compound eyes, the two mushroom bodies, in.b., 

 the ocellar nerves, oc.n., connected with the two lateral ocelli, 

 and the fontanel nerve, f.n., connected with the frontal gland, 

 f.g. To the deutocerebrum belong the antennal lobes, a.L, and 

 the antennal nerves of the antennae. The tritocerebrum con- 

 sists of the tritocerebral lobes, and the tritocerebral commissure, 

 tr.cm., beneath the esophagus. The labrofrontal nerves, l.f.n., 

 or the tritocerebral nerves, arise on the inner, median surfaces 

 of the tritocerebral lobes, and running upward and fonvard unite 

 in the frontal ganglion, fr.gn., which lies anterior to the main 



