20 C. HERBERT HURST. 



have a fully-developed spiral thickening. The portions connected 

 with the first abdominal stigmata, though better developed than the 

 portions connected with the other stigmata of the abdomen, have 

 the spiral thickening only slightly developed. The terminal portion 

 is beset with very luimerous small spines. 



The fate of the invaginated portion of the larval siphon is 

 interesting. The whole of the tissues composing it break up and 

 undergo complete absorption, so that no trace of it is discoverable in 

 the advanced pupa. 



Before dismissing the respiratory system, I will again state that 

 the pupa breathes air only, and breathes it through the open 

 stigmatic horns or siphons alone. The tracheal gills of Palmen have 

 no existence. 



The Muscular System. 

 Concerning this I have nothing new to communicate. The muscles 

 /^ of the pupa are those of the imago. All the chief ones are present 

 in the young pupa, but they increase greatly in size, and this is 

 especially true of the thoracic muscles. 



The Nervous System. 



The nervous system is particularly interesting. Within the short 

 space of four days, certain ganglia increase enormously in size by 

 the addition of cells apparently derived directly from the epidermis ; 

 and other ganglia, already well developed and functional, shift bodily 

 from their original positions, and in some cases fuse Avith ganglia 

 originally remote from them. 



• Kaschke {op. cit.) says that in the larva each of the first eight 

 segments (of the abdomen) has a pair of ganglia, and this statement is 

 certainly true of all the larvae I have examined, and yet a pupa which 

 I killed when only half escaped from the larval cuticle had already 

 four pairs in the thorax, and none in the first segment of the abdomen. 

 During pupal life these four ganglionic masses fuse into one compact 

 mass, though its composite nature is always recognisable in sections. 



The ganglia of the eighth segment (of the abdomen) at the 

 beginning of pupal life occupy their typical position in the anterior 

 part of the segment, and are connected with the ganglia of the 

 seventh segment by connectives (or " commissures ") nearly equal in 



