14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



The more distal tooth of the right mandible is actually double, there 

 being another smaller tooth immediately beneath it, arising from the 

 ventral surface of the mandible rather than from the inner edge as do 

 the others (fig. 2 F). There is no definite molar surface on the inner 

 face of the mandible, but the edge is divided longitudinally so that a 

 groove is formed, extending from the dorsal condyle (mad) to the 

 base of the tooth (niat). In the floor of this groove and about mid- 

 way on the inner face is an oblong foramen (prf) from which ex- 

 tends a membranous lobe or prostheca (prth). This lobe is nearly 

 one-third as long as the entire mandible and half as wide, and its 

 inner edge is regularly divided into a series of equal lobes, about 15 to 

 20 in number. The entire structure is densely clothed with minute 

 hairs. 



Near the lateral edge of the dorsal aspect of the mandible is a 

 shallow fold (fig. 2 J, inaf) extending from the condylar region at the 

 base to the end of the expanded proximal part of the mandible. Under 

 this fold are the openings of a series of pores (spe) which apparently 

 communicate with the interior cavity of the mandible. They lie nearly 

 parallel to the dorsal surface of the mandible and project mesad from 

 the fold. They may be branched (fig. 2 E) or unbranched, but the ij 



tip of each branch forms a capsule, the walls of which are traversed ■ ' 



by numerous small canaliculi (can), which are little larger than the 

 canaliculi normally found in most sclerotized integuments. 



Just distad of the anterior end of the fold (fig. 2 J, niaf) and at 

 the lateral edge of the mandible there appears to be another pore 

 (nip). This is not connected with the serial pores of the fold, but 

 under high magnification is seen to be merely a thinning of the sclerotic 

 wall in the form of a narrow sac or tube on the inside and a slight 

 indentation of the outer surface (fig. 2 I). The reason for the ex- 

 istence of this structure as well as of the serial pore organ is entirely 

 unknown to me. 



The mandible is articulated with the head by means of one dorsal 

 and one ventral condyle. The dorsal one is situated on the gena (fig. 

 2 J, mad) and the ventral one on the mandible (fig. 2 F, mav). The 

 dorsal articulation is an hemispherical acetabulum on the mandible 

 which fits over a spherical projection of the head capsule immediately 

 in front of the eye. The posterior articulation is a spherical projec- 

 tion on the base of the ventral or outer face of the mandible. It fits 

 into a crescent-shaped acetabulum at the anterior extremity of the 

 crassa. 



The maxillae (fig. 2 G) are situated immediately ventrad of the 

 mandibles at each side of the labium. Each is composed of four parts, 



