(30 JOURNAL, OF ENTOMOLOGY AND ZOOLOGY 



been tried with little effect. A number of parasites are named 

 and described in this bulletin. The most satisfactory way to 

 liold tliese in check is by the ordinary lime-sulphur spray some- 

 what diluted. C. A. Perrin. 



TTTE STRUCTURE AND METAMORPHOSIS OF THE 

 FORK-GUT OF CORY DA LIS CORNUTUS L. 



EOBERT MATHEWSON 



Jour, of Morph., Vol. 23, No. 4, 1912. 



The fore-gut has live well marked regions: pharynx, esoph- 

 agus, gizzard, portion between esophagus and esophageal valve, 

 and esophageal valve. 



The pharynx is provided with a series of dilator muscles 

 attached to the walls of the head. The esophagus has a large 

 number of longitudinal folds. The gizzard has powerful teeth, 

 which from their arrangement and the arrangement of the 

 muscles in this region, seem to show that they are for grinding 

 and crushing. The esophageal valve is short and is lined with 

 four strongly chitinized I'idges which alternate with the caeca. 



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

 The larval epithelium becomes partly 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 connection with the 

 basement membrane. The histolysis and histogenesis of the 

 muscular coats are also generalized processes. The muscles 

 liipiefy in place. The greater number of the larval nuclei be- 

 come rejuvenated and around them as centers the new fibrillar 

 structures are developed. 



The role of the leucocytes is a comparatively unimportant 

 one. They are present throughout pupal life and seem to 

 engulf small particles of the broken down tissues. They do not 

 take active part in the destruction of the larval muscles or 

 epithelium. 



The paper is illustrated b.y four plates from very tine photo- 

 graphs. 



