NEW MALLOPHAGA. 449 



tooth is shorter than the other, not so thick, and has a 

 rounded termination. Its anterior border is just visible 

 from the ventral side of the head, in front of that of the 

 ventral tooth. 



In Eurymetopus and in a large number of other genera 

 of the Mallophaga there occurs a very curious pharyngeal 

 sclerite with accessory structures, within the cavity of 

 the head. It is not intended here to explain the origin 

 or function of these, but merely to describe them. 



The sclerite referred to is a thick, strongly chitinous 

 structure situated in the ventral wall of the pharynx, and 

 is probably a greatly modified portion of its chitinous 

 cuticle. In a mounted specimen it is plainly visible through 

 the head from either the upper or the lower side. Lying 

 ventral to the sclerite are two structures which appear to 

 be glands, and are connected with it by a duct. All three 

 of these structures are visible through the head of cleared 

 and mounted specimens, and lie just back of the anterior 

 edge of the labium. 



This oesophageal sclerite (plate lxii, figs, i, 2, 3 and 7) 

 is in general form cup-shaped, having the hollow part 

 turned upward and forming a depression in the floor of the 

 pharynx, since its interior is simply a part of the pharyn- 

 geal cavity. The ventral surface is very convex, being 

 almost hemispherical. The anterior end is truncated, but 

 from each of the two anterior angles thus formed there 

 projects forward, outward, and dorsally, a large dorso- 

 ventro-laterally flattened process, which lies in the lateral 

 wall of the pharynx, the two partly surrounding the cavity 

 of the latter. Each of these processes is expanded distal- 

 ly, and sends a long, rounded, and bluntly terminated 

 projection backwards. These latter processes lie parallel 

 with and a little external to the lateral maro-ins of the 

 body of the sclerite, their outer edges being visible from 



