CHANGE FROM NYMPH TO ADULT. 607 



lamellfe and lamellar hairs of the adult may now be 

 distinctly seen. 



18th. — A great change has taken place in the ali- 

 mentary canal ; the old ventriculus is enormously dis- 

 tended and globular ; there seems to be a small fracture 

 at the top of it, the caeca are vague and almost hidden 

 below the ventriculus. The preventricular glands are 

 now small and much lower down than the top of the 

 distended ventriculus. The new pseudo-stigmatic 

 organs (of the adult) are now plainly seen, they are 

 further back than the coxae of the fourth legs of the 

 nymphal skin. The formation of the muscles running 

 to the new legs is apparent. 



19th. — The old ventriculus has again enlarged 

 slightly. 



21st. — The ventriculus has become shorter and 

 wider ; a considerable amount of light brownish matter 

 has collected along its anterior edge. 



22nd. — Scarcely any change. The nymphal skin 

 shows more prismatic colour by reflected light, and 

 the organs of the new cephalothorax are less distinctly 

 seen, as if there were air between the old and new 

 skins. The muscles at the sides are becoming more 

 complete. 



23rd. — The old ventriculus is lessening and travel- 

 ling more forward. 



24th. — The same process is continuing. 



25th. — The caeca have become larger and rounder ; 

 a new colon may now be seen forming inside the debris 

 of the old one, 



26th. — The ventriculus, &c., continue to travel for- 

 ward, a new rectum may just be seen. 



27th. — The alimentary canal continues to travel for- 

 ward, the old ventriculus has a concave hind margin ; 

 the old colon has nearly disappeared. 



30th. — The old colon has entirely broken up and 

 gone ; the new rectum is quite distinct. 



May 1st. — The alimentary canal has travelled for- 

 ward until the preventricular glands nearly touch the 



