SOUTH AFl.'lOAN TKKM ITKS. 21 



development of the long-itudiiial trachea-; except in the case 

 of the costa, which is not preceded by a trachea. That th(; 

 costa is not preceded by a trachea is confirmatory of the 

 views of Fritz MiUler, Spuler, Brauor, and Hedtenbacher. 



(6) From the examination of Cal oter mes durljanensis 

 Hac, the fundamental or primitive scheme would appear to 

 be for the ribs, Radius, Media, and Cubitus to be associated 

 with the main wing-sac trachoce which arise separately from 

 one another from the spiracular trunk trachea; of the thorax. 



(7) The variation in the venation, so decidedly charac- 

 teristic of the termite wing, is chiefly due to the erratic 

 development of the tracheas of the wing-sac. 



(8) The extra principal ribs frequently met with in a 

 termite wing are due to the growth of extra principal Iracheie 

 in the wino--sac. 



(9) The specialisation of the wing-ribs, ajjart fi-oiii the 

 costa, is one of reduction; first, in the degree of branching, 

 and then in complete atrophy. This is dependent upon a 

 more or less equal reduction in the tracheie of the wing-sac. 



(10) The respiratory system of a newly-hatched termite 

 consists of a framework of comparatively few simple tracliea>, 

 from which a multitude of dichotomising, arborescent, find 

 other trachea? gradually develop and grow. 



(11) The specialisation of the respiratory system is one of 

 reduction, the nascent system of the more specialised termites 

 (Metatermitidee) being less extensive than is that of the 

 more generalised termites (Protermi tidie and .Mesotermi- 

 tidte). The principal difference is the presence of a pair of 

 ventral longitudinal trunk trachecU in the Pro- and Mcso- 

 termitidie and the absence of such in the Meta teriiiitida- . 



(12) The valvular spiracles of the al)domen of an adult 

 termite are derived l)y gradual traiisforniatiou tVoui the 

 occluding apparatus of the spiracles with a lixed opening 

 exhibited by the nymphs ; and this transformation is more 

 decided in the females than in the males. 



(13) The slit-like spiracles of the abdomen of highly dis- 

 tended females (queens) of the Holmgren genera Termes and 



