BRAINS OF THEEE GENERA OF ANTS 



547 



three genera under consideration may be graded as follows: Cara- 

 ponotus, figures 1 to 3, queen, worker, male; Lasius, figures 7 to 9, 

 queen, worker, male; Formica, figures 4 to 6, worker, queen, male. 

 The sections drawn in text figure 2, from Camponotus, all 

 taken through the point of exit of the antennary nerves, show 

 that at this point the entire antennary lobes of the queen and 

 worker are about equal, although the fibrous core in the queen 



Text fig. 2 Sections of the brain of Camponotus pennsylvanicus through the 

 antennary lobes at the point of exit of the antennary nerves. A, queen, B, 

 worker, C, male, a.l., antennary lobes; a.n., antennary nerves; oc, ocellus. 



A, is much larger than in the worker, B. Posterior to this 

 region the fibrous core of the queen decreases in size and the 

 cell envelope increases, but the fibrous core of the worker is 

 never larger than in this figure. 



Pietschker finds these lobes larger in the worker than in the 

 queen. On page 88 he states: ''Der Lobus olfactorius besitzt 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 23, NO. 6 



