DEVELOPMENT OF THE ANTENN.1<: OF TEHMITES. 283 



Imago. — In view of the absence of any compound joint in 

 the flagellumof the XX imago organ (fig. 11), its development 

 appears regular from stage A to stage P. Lnter it mav reach 

 the stage Pb, when, by the exceptional abjunction of (18) as 

 an orphan-joint, a XXI-jointed organ originates. The III of 

 the XX expression may well be regarded as comprising 6 joint- 

 elements showing the flagellnm to comprise 23 elements. 



Major Soldier. — Ordinarily the antenna? are XYII- 

 jointed (fig. 11, d), IV being a little coarser than either HI or 



Text-fig. 11. 



Rhinotermes putorius Sjostedt. a. Imago. />, c,cZ. e. Major 

 soldier. /, </. Major worker. i,j. Minor soldier, k. Minor 

 worker. 



V. In most there is little else than its coarseness to indicate 

 IV as a compound (15-f-14j; this is, however, revealed in the 

 organ represented by (c), which happened to be tlie com- 

 panion of that of (d). The XVII is therefore derived from 

 the X^^III, (6), by the (15 + 14) combination ; but in view of 

 the greater length of III in these expressions, the XVIII- 

 jointed organs appear to be arrested at stage K, and the XVII 

 at stage JM. Therefore, in the XVIII expression, III com- 

 prises 4 elements and, in the XVII, 6 elements, thus illustrating 

 a greater development although the total of joints is less. 



One major soldier was found with both antennae of XVI 

 joints (fig. 15, e), and fr-omthe condition of III this is regarded 

 as the result of arrest on reaching stage J. 



VOL. 4, PART 2. 20 



