FORE-GUT OF CORYDALIS CORNUTUS L. 611 



observed the rhythmic contraction and expansion of the gizzard 

 in Uving Vespidae (Vespa crabo). 



4. The gizzard does not pass directly into the oesophageal 

 valve but is joined to it by a short, more or less smooth, tube. 



5. The oesophageal valve is short and is lined with four strongly 

 chitinized ridges which alternate with the caeca. At the point 

 of union of the epithelium of mid- and fore-guts there is located 

 a peculiar group of glandular cells whose function is doubtful. 



6. The metamorphosis of the fore-gut is of a generalized type. 

 The larval epithelium becomes partially broken down and the 

 cells destroyed are replaced by the division of rejuvenated larval 

 cells. The nuclei always divide mitotically and every spindle is 

 located at the side of a vacuole. The dividing cell migrates 

 towards the inner surface, though it retains a connection with the 

 basement membrane. 



7. The histolysis and histogenesis of the muscular coats are 

 also generalized processes. The muscles liquefy in place. The 

 greater number of the larval nuclei become rejuvenated and around 

 them as centers the new fibrillar structures are developed. 



8. The role of the leucocytes is a comparatively unimportant 

 one. The leucocytes are present throughout the pupal life and 

 are seen to engulf small particles of the broken down tissues. 

 They do not take any active part in the destruction of the larval 

 muscles or epithelium. 



