SOUTH AFRTCAN TERMITIIS. 45 



trunk as are other ventral commissures, and that its bases 

 have fused into the leg-tracliea'. If, then, the tracheiB of the 

 mouth-parts are directed ventrally, they correspond Avith 

 the leg-trachete. These alterations appear in the diagram 

 fig. 47 (PI. V). This diagram illustrates that (a) the trachea 

 penetrating the anterior lateral and doi-sal extension of the 

 prothorax corresponds with the visceral trachea of spiracles 

 V to X, and is not a wing trachea, as might be readily 

 supposed; {h) the trachea of the antenna is the homologue 

 of caudal trachea. The tracheee of the gena and vertex are 

 probably analogous to the arborescent tracheae which develop 

 from the buds of the dorsal longitudinal trunk. The difference 

 is that there ai'e two instead of one, but it frequently happens 

 that two arborescents arise from a section of the trunk, and 

 it is not altogether rare foi- one section to be budless and 

 one or the other of those adjoining to possess two buds. 



The complexi oF the frons and of the clypeus appear to be 

 without homologues. 



Although the visceral tracheae are regularly confined to the 

 palisades V to X, occasionally, and as a later development, 

 an analogous branch may arise from palisade IV; this is 

 included in fig. 47 (PL V). 



From fig. 18 (PI. Ill) it will be seen that the tracheal twigs 

 which enter the glossae, paraglossee, and labial-palpi have 

 their homologies in the twigs entering the laciniee, galeae, 

 and maxillary-palpi. Further, the tracheee of the mandibles 

 are homologous to those of the labial mouth-parts insomuch 

 that each extends to the apical tooth, and sends one branch 

 to the cutting region and another to the molar region of each 

 mandible. In this connection it may be mentioned that the 

 mandible of the nymph of a Eutermes (trinervius grouji) 

 strikingly exhibits three well-defined regions; the apical tooth 

 being the homologue of each palpus, the cutting region of the 

 galea and paraglossa, and the molar region of the lacinia and 

 glossa. (See inset on PI. IV.) 



