160 CALIFORNIA ACADEMY OF SCIENCES. 



also, the neck is shorter. The ventriculus with its 

 large gastric cseca is about the same. Nitzsch (1874) 

 figures the alimentary canal of T. clmiax. Here the 

 crop differs somewhat from the two just described in 

 that the neck is very much shorter, the crop forming 

 a pear-shaped diverticulum from the side of the oesoph- 

 agus and separated from it by a narrow constriction. In 

 this form the distal end of the crop is the larger, while 

 in the Philopterid forms the proximal end is the 

 larger, the distal end being generally more or less 

 tapering and pointed. No intermediate form of a crop 

 between the Philopterid and Trichodectid types has 

 been found, and it is impossible to say which is the 

 more primitive. 



Pharyngeal Sderite. — In many genera, including all of 

 those of the Ischnocera, and one and part of another 

 genus in the Amblycera, there is present a curiously 

 formed sclerite in the walls of the pharynx. It has 

 already been described in Kellogg's "New Mallophaga, 

 II," under the term " cesophageal sclerite." As shown 

 there, it is a prominent, cup-shaped thickening of 

 the chitinous lining of the ventral wall of the phar- 

 ynx, forming a depression in the latter. From its 

 sides (plate x, fig. 7) chitinous bands (bs) run upward 

 around the pharynx and are connected by muscles with 

 the dorsal wall of the head. From the anterior corners 

 a large expansion (ant. h) on each side reaches forward 

 and upward in the walls of the pharynx. Into the ante- 

 rior end of its cavity a duct from two ventrally situated 

 glands opens. The latter (plate x, fig. 2, l.g.) are oval, 

 covered with a chitinous envelope, and supported by chi- 

 tinous pedicles. From the anterior end of each a duct 

 runs forward, after traversing the ventral surface, and 

 then turns inward and backward to unite with the duct 



