BRAIN OF THE 'WHITE ANT 569 



ward for some distance, evidently giving fibers to and receiving 

 fibers from the posterior cells of the mushroom bodies, and then 

 ending in about the same plane with, the beginning of the trito- 

 cerebral lobes. 



c. Comparison of the mushroom bodies of the different castes of 

 L. flavipes. The mushroom bodies differ Uttle in the different 

 castes except in size, and even in this respect there is not a very 

 great dissimilarity (figs. 8 to 12). 



The worker has the largest mushroom bodies, largest by actual 

 measurement and in the estimated number of nerve cells; the 

 nymphs of the fir>t and second forms have mushroom bodies 

 about similar in size, but slightly smaller than those of the 

 worker; the soldier has the smallest mushi'oom bodies of any 

 caste. The cells of the mushroom bodies of the worker- and 

 soldier penetrate into the intercerebral region (figs. 22, 25), but 

 merely border upon it in those of the njTuphs of the first and 

 second forms. 



My only true adult material, as already stated, was alcoholic 

 and much of it seemed to have shrunk. It will be noted that in 

 the true adult brain outlined in figure 9 the mushroom bodies are 

 farther apart than in the n>aiiph of the first form from which 

 this adult has developed (fig. 8) and the frontal gland has in- 

 creased in size. Some other better preserved true adult brains 

 are considerablj' larger than the brain of a npuph of the first 

 form, and the muslu-oom bodies are likewise larger. 



Holmgren ('09) emphasizes the great deterioration of the brain 

 tissue which he observes in the older enlarged and egg-laying 

 queens. IVIy material has been preserved in alcohol and is not 

 the best for finer study, but the examination of several old and 

 enlarged queens leads me to believe that in L. flavipes this 

 deterioration of the brain has not taken place. 



d. Comparison of the 7?iushroom bodies of termites and hymenop- 

 tera. A comparison of the Leucotermes mushroom body with 

 those of ants and bees shows, as one would naturally expect, 

 that the termite muslu-oom body is much more simple and 

 primitive. This primitive condition is apparent in the small 

 and uniform size of all the nerve cells, especially in the cell 



