254 



CLAUDE FULLER. 



met with, as it is the less involved and the results are the 

 same. It may be described briefly as follows : In the mono- 

 locular form (a) III contains four elements in a more or less 

 compressed condition. These represent two paii-s, and of 

 each pair the proximal element is the smaller. With ihe 

 growth of the distal pair III becomes bilocular {h), and from 

 this it passes through a faintly to a distinctly trilocular 

 state (c), when two new elements arise. Subsequently the 

 two outer loculi abjunct as rudimentary joints {d) and III 

 reverts to its monolocular form as the receptacle of four 

 elements, two of which are new. Speaking generally, the 



Text-fig. 3. 



Diagrams illustrating the external and internal metamorphoses of 

 joint III and the ahjuncting of rudimentary joints. 



number of abjuncted joints in the flagellum of the newly 

 hatched termite is either seven or nine. Hence the last 

 abjuncted joint in a developing organ is the odd number of a 

 pair, e.g. 9, 11, 13, 15, etc., the pairs being (8-9), (10-11), 

 (12-13), (14-15), etc. This fact may be made use of in 

 determining the condition of antennae developing by the second 

 mode; if what appears to be the last joint abjuncted has an 

 even number, when counted from the apex towards the scape, 

 it is because its companion has not been distinctly segmented 

 oif from the stem. 



With both modes there is a decided tendency for the 

 articulation, or line of fission, dividing paired or sister 

 elements to become suppressed. This results in the abjunc- 

 tion of a compound joint, and if the articulation is quite 



