590 CAROLINE B. THOMPSON 



form, with short wing pads, the soldier, the worker, and, to 

 some extent, the true adult. 



1. There is no differentiation between the brains of the males 

 and females of any caste or stage of L. flavipes. 



2. There is very little differentiation between the brains of 

 the different castes and stages of L. flavipes here discussed. 



a. The most marked differentiation is in the optic apparatus, 

 a correlation existing between the degree of development of the 

 compound eyes and the size of the optic lobes. The latter are 

 large in the nymphs and adults of the sexual forms, but are 

 greatly reduced in the worker and soldier. 



h. The mushroom bodies differ very little in size, by actual 

 measurement and in the estimated number of cells. They are 

 largest in the worker, smallest in the soldier, and are inter- 

 mediate in size in the sexual forms, although the mushroom 

 bodies of the true adult are nearly as large as those of the worker. 



c. The antennary lobes are very similar in size, but are largest 

 in the worker and in the sexual forms and slightly smaller in the 

 soldier. 



3. The mushroom body stalks do not end beneath the central 

 body, as was formerly thought, but divide into three roots, the 

 anterior, central body, and posterior roots. The latter are ex- 

 panded into large and prominent lobes. 



4 The labral nerves arise from the ventral surface of the 

 frontal ganglion, and not directly from the labrofrontal nerves. 



5. The termite brain as a whole is very similar in structure to 

 the brain of ants, with the notable exception of the mushroom 

 bodies which are of a much more simple and primitive type. 

 This is apparent in : (a) the nerve ceUs, which are all very small 

 and of equal size, (6) the separation of these cells into three 

 groups, instead of the four of ants, (c) the incomplete separation 

 of the two lobes. 



Only the two lateral simple eyes or ocelli are present in the 

 nymphs and adults of the sexual forms, and none are found in 

 the worker or soldier. These ocelli are very simple and primi- 

 tive in structure, without lens or pigment, and the ocellar nerves 

 do not expand into ocellar lobes as in ants. 



