24 C. SASAKI. 



The digestive canal (PL IV, fig. 11 ) begins with a mouth which 

 is followed by œsophagus, proventriculus, chylific stomach, ileum and 

 rectum, and finally ends at the anus opening on the last segment of 

 the maggot. The mouth is provided with a hooked jaw (fig. 11 ja ) 

 of a dark brown color, which may be either projected or retracted at 

 will. The root of the jaw which lies within the anterior segments of 

 the maggot is parted into two white lobes, showing that tlie hooked 

 jaw is formed by an amalgamation of 2 similar jaws. Into tlie oeso- 

 phagus opens a common duct of two salivary glands (fig. 11 a ), each 

 having the form of a long cylindrical sac. Its walls are composed of 

 delicate glandular cells, provided with large nuclei (PL IV, fig. 12). In 

 the mature maggot, these sacs are always filled up with saliva; this is 

 the very material with which the maggot moistens and softens the co- 

 coon of the silkworm while getting out of it, and with which the mag- 

 got sticks together fats snd muscles of its host in the trachea of the silk- 

 worm so as to form a sort of cup for its own lodgement. The proven- 

 triculus (fig. 11 c) is in the form of a globular sac provided close to 

 its posterior end with a pair of blind sacs (fig. 11 f). The chylific 

 stomach (fig. 11 eh ) is a convoluted tube which is much longer in 

 ength than the ileum and rectum (fig. 11 U, r ). At the junction of 

 the chylific stomach and the ileum, there are provided two malpighian 

 vessels (fig. 11 m ), each of which again bifurcates into two branches. 

 These branches are long and slender, and have the aspect of a zigzag 

 line. They are colored light yellow, and their free ends which are 

 somewhat widened are wliite. One of these two branches is directed 

 anteriorly, and the other posteriorly. These vessels are composed of a 

 long canal, in the walls of which are imbedded large delicate cells 

 ( PL IV, fig. 13 ), each containing a large nucleus in the centre. The 

 contents of the cells are granular and tinged light yellow, and to 

 the peculiar arrangement of these cells is due the zigzag appearance 



