256 CLAUDE FULLEE. 



or less from III, and tlie compound which III itself 

 represents. 



The several points in the foregoino^ discussion may be 

 illustrated hypothetically by fig. 4, a-f. Diagram a repre- 

 sents a X-jointed expression with III monolocular; in h 

 the bilocular and in e the trilocular conditions ai^e given. 

 Ordinarily the increase in the number of joints is as repre- 

 sented in d, in which the two new joints are (8) and (9) and 

 the X expression has definitely become a XII expression. 

 Should the articulation between (8) and (9) be suppressed 

 and the two abjuncted as a compound joint the X will become 

 an XI expression as in e. Should the process subside more 

 or less suddenly, whilst in the stage of c, a long III will form 

 about the six elements then present, and the organ will 

 remain X-jointed. If the subsidence is more gradual, one 

 joint (8) will abjunct, as in/, and give rise to an Xl-jointed 

 organ of which III encases five elements. 



(5) Embryonic Development. 



The development of the antenna has two stages, the 

 embryonic and the post-embryonic. The degree of develop- 

 ment when the Qgg hatches appears to differ in different 

 species. Thus the young of Cryptotermes shortly after 

 birth have organs specifically X-jointed, but which may 

 appear VIII- or IX-jointed. The antennae of most species 

 are, at hatching, X-jointed with the elements of XIII ; others 

 again are XII with the elements of XV. Joint III thus 

 contains four joint-elements in the form of two sister pairs. 



The embryo at maturation possesses organs having the 

 appearance of elongate sacs attached to the two-jointed 

 scape. Within these sacs a series of septa may be seen of 

 which those towards the apex are the more distinct. The 

 impression one gathers is that the scape develops first and 

 the flagellum is produced therefrom ; but a definite study of 

 the embryology is much to be desired. 



