68 B. GRASSI AND A. SANDIAS. 



the base of the cylindrical cells are interposed scattered 

 small cells (replacement cells ?). Ventricular cseca are 

 absent. 



The intestine is more or less dilated in front, rather nar- 

 rowed and more curved in the middle (giving a curvature to 

 the whole region), and dilated again posteriorly (rectum). 

 The rectum possesses six longitudinal folds (plicse rectales) 

 of large size and rich in glandular cells ; each of them receives 

 the ramifications of a tracheal branch. 



The Malpighian tubules are long, with a somewhat ample 

 lumen filled with solid excrementitious matter. Their number 

 varies with age, and as many as twenty may be made out in 

 the adult ; perhaps the number may be still larger. Further 

 appendages of the alimentary canal are the two salivary glands. 

 These lie on each side of the thorax, and are lobulated ; each 

 has a special efferent duct dilated towards the middle, the ducts 

 uniting in front to form a common canal which opens on the 

 labium. These efferent ducts possess a spiral thread like the 

 tracheae. 



I may here mention the sericigenous glands of the anterior 

 legs. As I have stated, the lower border of the first tarsal 

 joint is set with abundant short spines, among which is a row 

 of less numerous setse, curved at the tip, and perforated by a 

 very fine canal. These canals open externally, in my belief, 

 at the somewhat blunt apex of the setse, and extrude from 

 time to time a drop of transparent secretion ; at their base they 

 terminate in a complicated manner in multicellular glands, 

 a number of M^hich fill the greater part of the joint. Tubular 

 setse are also found beneath the second tarsal joint, but I have 

 not detected the corresponding glands ; perhaps they com- 

 municate with glands in the basal joint. 



Other special organs are the papillae of the middle and pos- 

 terior tarsi. They possess a rather thick cuticle, more or less 

 clearly divisible into two layers, and marked in places with 

 distinct striae (pore- ducts?). Threads of silk may often be 

 noticed adhering to these papillae. 



The function of these tarsal organs, which show a certain 



