532 CAROLINE BURLING THOMPSON 



Berlese in his figure 681 shows three ocellar lobes above the 

 posterior dorsal commissure, or ''ponte dei lobi protocerebrali." 

 In a note he quotes Cuccati, referring to figure 685, ''II nervo 

 degli ocelli pari receve fibre che partono dalle punte estreme del 

 ponte dei labi cerebrali ed altre che partono da cellule ganglionari 

 della parte antero-§uperiore del procerebro." It would seem 

 that the fibers said by Cuccati to be received by the ocellar lobes 

 from the apex of the ''protocerebral bridge," the posterior com- 

 missure, were probably leaving the ocellar lobes by way of the 

 commissure, as they are described in this paper in male ants. 



These different accounts show that there is evidently much 

 variation in the structure and arrangement of the ocellar lobes 

 and the ocellar nerve fibers of insects. 



5, THE OPTIC BODIES 



The optic bodies, so called by Kenyon, a translation of Vial- 

 lanes' term, ''tubercules optiques," are two very small lolbes on 

 the ventral surface of the anterior part of the protocerebral lobes 

 (fig. 10, 0.6.) . These structures are very small lobes of the fibrous 

 core with small bundles of fibers running out from them to the 

 surrounding nerve cells, but they are present in all three castes 

 of the three genera here described. Pietschker ('10, p. 79) states 

 that he does not find these bodies in Camponotus ligniperdis. 

 Jonescu ('09) finds them in the honey bee, in a situation similar 

 to that described for ants. 



6. THE OPTIC LOBES 



The optic lobes of the three genera under consideration con- 

 sist of the three outer, middle, and inner fiber masses described 

 in other ants and in bees. A very marked variation in the size 

 of these lobes is observable in the different castes and in different 

 genera, and was discussed in the section dealing with the com- 

 parison of the castes. The finer structure of the optic lobes has 

 been so exhaustively described that it has been omitted from 

 the present study. 



