SOUTH AI'MMOAN TKl^MITEvS, 93 



Fig. 45b. — Outside aspect of the disrupted spiracle of the distended 

 female of T. natalensis, sliovving the mouths of the tracheae and the 

 tracheate character of the disruption. 



Fig. 46. — Diagram of the tracheal stem (Metatermite) of the head 

 and thorax. 



Fig. 47.— Diagram of the tracheal stem (Metatermite) to illustrate 

 homologies. 



Fig. 48.— Diagram of a section of the tracheal stem of the Calo- 

 termite type, to show that the wing trachea? originate from the 

 spiracular trunk ; both the dorsal longitudinal and the ventral longi- 

 tudinal traehese being present. 



PLATE VI. 



Fig. 49. — Thorax of a yovmg Cryptotermes nymph, illustrating the 

 latei'al bulging out of the spiracular trunk (shown in solid black) within 

 the meso- and metathorax. 



Figs. 50a, b, c. — The genesis of a trachea bud in three stages of 

 development ; as found on a series of tracheal pipes in the abdomen of 

 a Calotermes nymph. 



Fig. 51. — The buds of wing tracheae. 



Fig. 52. — Clavate tubercles of wing tracheae. 



Fig. 53. — Conical tubercles of wing tracheae. 



Fig. 54. — The sub-apical growth of tracheae from tubercles. 



Fig. 55. — Wing - sac of very young nymph of Odontotermes 

 latericius with a simple conical bud (the radial) and a furcate bud 

 (the cubital). 



Fig. 56. — The bud of the post-costal (Pst. c.) on base of radial (K.). 

 (Cryptotermes.) 



Fig. 57. — The vermiform bud of sub-costal (Sc.) on radial. (Crypto- 

 termes.) 



Fig. 58. — Early form of anal (A.) on cubital (Cu.). (Cryptotermes.) 



Fig. 59. — Fore and hind wing-sacs of Cryptotermes, showing the 

 early form of the six princijDal trachete. 



Fig. 60. — The lateral tracheae of the thorax of Cryptotermes; 

 ((.a.a., doi'sal longitudinal ; b.f.b., spiracular trunk ; c, first spiracle of 

 abdomen; d., second spiracle of thorax; e.e.. arms of leg tracheae; 

 </., stem of leg trachea. 



Fig. 61. — Wing-sac of full-grown nymph (T . natalensis), illustrating 

 the beginning of the growth and folding of the final wing, accompanied 

 by the displacement and coiling up of the tracheae. Tracheae in focus 



