288 CLAUDE FULLER. 



variable, but may be described as an VIII rising to X. In 

 the second instar it is XII (fig. 12, h). 



The variableness of soldier antennre may be attributed to 

 the subsidence of joint-multiplication in both the second and 

 third instars ; but why, in some cases, one antenna should be 

 affected earlier than its companion cannot be any more 

 readily explained than why both of one insect should be 

 earlier affected than both of another, unless the asymmetry 

 of the antenna of the two sides arises from asymmetrical 

 castration. 



The rare X-jointed organ represents a development in 

 which no annulations are formed after the first instar, i.e. at 

 stage A, whilst the XV-jointed represents a development 

 beyond stage G. 



(9) Cryptotermes sp. Fig. 13, a-h. 



Antennal Index. — Imago XVII, XVI, XV ; soldier XV, 

 XIV, XIII, XII, XL 



This is a fairly common species ranging along the littoral 

 of Natal. It may or may not be a described form. It is one 

 from which the soldier caste seems to be in the process of 

 elimination, as I only succeeded in obtaining 21 examples 

 from four communities. 



The specialisation of the soldiers, as apart from features of 

 reduction, may be described as an extraordinary degree of 

 cephalisation, and this has a very decided influence upon the 

 form of the final antennas. The basal section of the flagellum 

 is composed of an ill-defined series of annulations, and its 

 condition is such that it foreshadows the form of the long III 

 in the antennae of Calotermes durbanensis. Farther, it 

 renders any counting of the joints unsatisfactory. Fig. 13, c, 

 represents a fairly well-defined organ of XV joints ; in 

 many, however, the definition is not so good. With most 

 the apical series (1) to (9) become well-defined and seem to 

 represent a development to D. Any antenna of apparently 

 less than XII joints may be regarded as arising from the 

 fusing of (9) with the rudimentary series. 



