132 CAROLINE BURLING THOMPSON ' 



6. In nymphs of L. flavipes with ten antennary segments, the 

 third segment grooved, and a body length of 1.3 to 1.4 mm., the 

 individuals of the reproductive type are further differentiated 

 into two groups: a, with large brain and large sex organs; h, 

 with slightly smaller brain and smaller sex organs. These are 

 the respective prototypes of the nymphs of the first form and the 

 nymphs of the second form, and hence of the two adult castes 

 of the first form, with long wings, and of the second form, with 

 short wing pads. 



7. The prototypes of the worker and soldier castes, although 

 externally alike, are distinguishable by internal structures at 

 the end of the second stage of development, in nymphs with a 

 body length of 3.75 mm., and are probably distinguishable at 

 an even earlier age. • 



8. The frontal gland is present, although barely reco^izable, 

 in the newly hatched nymphs, and grows larger and more com- 

 plex as development proceeds. The fontanelle nerve (median 

 ocellar nerve) is not present in the earlier phases, but is clearly 

 seen in individuals with a body length of 1.6 mm. From the 

 beginning, the frontal gland is larger and more differentiated in 

 individuals of the reproductive type than in the worker-soldier 

 type, and may be added to the hst of characters by which the 

 two types are distinguished. In individuals of the large headed 

 worker-soldier type, with a body length of 3.75 mm. two types 

 of frontal glands may be recognized: a small, primitive frontal 

 gland in the worker prototypes, a large, highly modified gland 

 in the soldier prototypes. 



9. No evidences of a prototype for the third adult reproductive 

 caste, without wing pads, have been seen in this study of the 

 development of L. flavipes. 



10. To simplify the heterogeneous nomenclature of the three 

 adult reproductive castes I have suggested the following terms, 

 which are in conformity with the terms applied to the oldest 

 nymphs since the time of Lfespes ('56) : 



1. Adults of the first form, or males and queens of the first 

 form (with long wings or stubs of wings) . 



