DEVELOPMENT OF THl^ ANTENN^T] OF TERMITES. 239 



consideration in species-building, and cases might be mentioned 

 where a disagreement of one joint has been regarded as 

 sufficient to distinguish two otherwise similar insects. Such 

 species must be accepted with considerable reservation. In 

 some groups the validity of a species may rest upon the 

 relative length of one joint to another or perchance upon the 

 ratio of the length and the diameter of certain joints ; these 

 criteria are fraught with error. Perhaps the most trying 

 point of a diagnosis is reached Avhen the author deals with 

 joint III, comparing its length with that of II or IV as, fancy 

 free, the eccentricity of the moment dictates. It is this 

 joint III — the elusive and misunderstood section of the termite 

 antenna — which is responsible for the present attempt to 

 show how the joints develop, how departures may and do 

 arise Avithin a species and a caste, and how such may be 

 homologised or understood. 



Any description of the antenna, particularly that of the 

 soldier, must long remain suspect and must be indefinitely 

 tested. Later, some account is given of certain soldiers of 

 Termes belli cos us with XVII-, XVIII- and XlX-jointed 

 antennte, all being normal developments. Of African ter- 

 mites, none has been more often the subject of reference than 

 this and none has been recorded from a greater number of 

 localities. Of its five castes, none has been more frequently 

 before the specialist than the major soldier, but never has 

 this been recorded as exhibiting an antenna of more or less 

 than XVII joints. Indeed, were one asked to select a species 

 which might, on good grounds, be regarded as having 

 antennas fixed in character, Termes belli cosus would be 

 it. And yet one nest-series of this great mound-builder was 

 obtained in the district of Lourenco Marques, of which as 

 many of the major soldiers had antennas of XVIII or XIX as 

 had the usual XVII joints. 



Fundamentally all termite antennae are built up of elements, 

 and these are expressed as articulated segments except when 

 two or more unite in part or completely to form compound 

 joints. Such joints maybe noticeably compound or they may 



