92 CLAUDE FULLER . 



reduced to form a narrow edge to C the tympanic chin-plate, and 

 L., the lever has developed a strong' thumb-like projection. The 

 trachelos (vi. tr.) is also seen within the open mouth of the spii-acle. 

 (The cuticle is not indicated.) 



Fig. 33. — Spiracle TV (the second abdominal) of T. natalensia, 

 female ; not so decidedly transformed as spiracle III. Lettering as for 

 fig. 3 2. 



Fig. 34.— Spiracle X (the last abdominal) of T. natalensis, 

 female ; still less decidedly transformed. Lettering as for fig. 32. 



Fig. 35. — Abdominal spiracle of Hodotermes, female, as seen from 

 the outside, showing the two thumT)-like projections to which the 

 muscles are attached. Lettering as for fig. 32. 



Figs. 36a, b, c.^ — The abdominal spiracles of Hodotermes. male, 

 fig. 36a, from without; fig. 36b, fi-om within, open; fig. 36c. from 

 within, closed. 



Fig. 37. — The rim (from within) of the spiracle of the second stage, 

 T. natalensis (fig. 24a), showing the hexagonal (tessellated) framework. 



Figs. 38a. b, c. — The thoracic spiracles of T. swaziaj. fig. 38a, the 

 second : fig. 38b, the first : fig. 38c. the second disrupted to separate the 

 occlusor from the extensor muscle drawn on a nnich sniallei- .scale than 

 38 a. 



Fig. 39. — The trachea^ of the femur in tlie half-grown nyutph of 

 T. natalensis. 



Figs. 40, 41. 42. 43a and 43b. progressive stages in the development 

 of the abdominal pipes of the female nymph of T. natalensis. 

 Fig. 40, the distension of the pipes ; figs. 41 and 42. two stages of 

 the growth of the multitude of dichotomising trachea" from the 

 pipes; fig. 41. p. com., palisade commissure: d. tr.. dorsal trunk; 

 r. com., ventral commissure ; sjj. tr.. spiracular trunk. Fig. 43a, an outei' 

 aspect of the tracheal arrangement about the abdominal spiracles of an 

 almost mature nymj)h, showing sp. t.. the spiracular trunk ; vc. vc, 

 ventral commissures; pc. pc. palisade commissures ; 0. C, the ovarian 

 chord embraced by two of the tracheal bunches. Fig. 43b, the inner 

 aspect of the arrangement represented by fig. 43a. showing two perpen- 

 dicular and one oblique muscle and the peristaltic ribbon. 



Fig. 44. — A side view of an abdominal spiracle of the adult female 

 (T. natalensis). showing L., the lever; tri.. the trachelos. and some of 

 the many dichotomising tracheje that open into the cup formed by the 

 trachelos. 



Fig. 45a. — A part of a disrupted spiracle of the distended female 

 (queen) of Odontotermes badius. showing how the trachea" open 

 freely into the disruption. 



