SOUTH AFRICAN TERMITES. 33 



system through sliort tracheal pipes. ^ Within the spacious- 

 ness of the liead and the narrow confines of the neck and 

 prothorax, the system is considerably modified ; however^ it 

 is not independent of the rest, and the homologies of many 

 of the parts there found with those of the thorax and 

 abdomen can be determined, notvvitlistaiiding the very 

 different appearance they present. 



Va. The Posterior or Body System. 

 Plate III, figs. 2-18. 



Considered apart from the head, neck, and prothorax, the 

 system posterior to the first pair of thoracic spiracles may be 

 said to be composed of four longitudinals connected by two 

 series of vertical and one series of transverse commissures. 

 For convenience the longitudinals will be distinguished as the 

 paired dorsal and paired spiracular trunks. There are 

 no ventral longitudinal tracheee. The upper pair, or dorsal 

 longitudinal trunks, take an undulating course below the 

 sides of the dorsum, extending from the prothorax to the 

 caudal segments. The lower pair or spiracular trunks lie 

 within the sides of the body against the spiracles, and are 

 composed of a series of loops which link up the pipes in a 

 .somewhat indirect manner. Each spiracular trunk is con- 

 nected with its corresponding dorsal by a regular series of 

 palisade or vertical commissui-es, and the two spiracular 

 trunks are directly connected by an equally regular series of 

 ventral, transverse commissures. The extensions are : (;i) tlie 

 tracheae of the second and third legs ; (b) the ingrowing 

 or visceral trachea, arising from each of the last six pairs "f 

 palisade commissures ; (c) buds of arborescent tracheae, set 

 almost regularly along the dorsal trunks ; and (d) paired buds 

 and twigs upon the ventral commissures. 



The examination of the arrangement in nymph after 

 nymph, a small point here and another there, leads to the 



' The term " pipe " is here used to distinguish the air passage leading 

 directly from each spiracle. 



VOL, 4, PART 1. 3 



