DEVELOPMENT OF THE ANTENNJ3 OF TERMITES. 253 



repeatedly. In the case of Hodotermes the joint certainly 

 has an analogous nature, but the addition of new joints is not 

 due to an obvious subdivision of the whole — indeed, the 

 rudimentary joints have rather the appearance of being 

 budded at the apex of II. 



Doubtless the mode of joint formation in III seen in most 

 species is a modification of the more generalised condition of 

 Hodotermes, arising from the slowing down of the process 

 and the production of fewer joints. To explain adequately 

 the difference in the mode of joint formation in Hodotermes 

 and in the remaining termites, a detailed embryological 

 investigation is essential. 



The cycle of external changes recurring in III is more 

 readily recognised in the antennce of some species than in 

 those of others. In some there is no difficulty encountered 

 in deciding, upon exterior features alone, what phase the 

 part is in ; in others one may be readily deceived. In the 

 former the subdivision results in the more or less coincident 

 abjunction of two joints of nearly equal development (fig. 8, 

 a-d). In the latter there is a decided difference in the 

 degree of development of the two joints, and the premature 

 incipient abjunction of the predominant partner gives the 

 impression that the joints arise one by one and leads to one 

 abjuncting joint being regarded as belonging to the formative 

 zone (fig. 3, e-g). This difference, at the beginning of my 

 study, led me to premise two modes of joint-multiplication — 

 the production of joints as pairs and as single individuals. 

 An examination of the internal metamorphosis shows, how- 

 ever, that the difference is but one of degree. Both modes 

 are illustrated in the accompanying series of diagrams. 

 Fig. 3, a-d, show the internal and external changes noted for 

 the one, and e-g for the other. A comparison of these two 

 modes indicates that on the coincident abjunction of two 

 joints III becomes monolocular in the one {d) and bilocular 

 in the other (g). 



The first mode may be used to describe the development of 

 all antencas and to explain the origin of the various patterns 



