580 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 5T 



plate, the surface of which is level in all genera except Thaneroclerns, 

 where a large unpaired tubercle is developed medianly. In some 

 forms the inner postmaxillary margin of hypostoma is on each side 

 separated as a Paragular plate (pgu), adjacent to the lateral margin 

 of gula. 



The Epipharynx {epx, fig. 116) forms the dorsal wall of the buccal 

 cavity; it carries a pair of large, rounded epipharyngeal plates 

 (epxp), which usually are fused in the middle line; they are slightly 

 chitinized, smooth, and without setae ; but a small group of short, very 

 stout, tooth-like setae occur in front of each. On the dorsal surface 

 of labium Lingua {lin, fig. 31) forms the anterior part of the ven- 

 tral wall of the buccal cavity ; it is equal in size to the exposed ventral 

 surface of labium, is thick, fleshy, and covered with sensory hairs 

 and papillae. The Hypopharynx (hy) forms the posterior part of 

 the ventral surface of the buccal cavity ; it is located above the men- 

 tum and as large as this structure. Anteriorly on each side of it is 

 found a free, bifid and tooth-like end of a rod-like vei-tical projection 

 from the ventral chitinous surface of stipes ; and, corresponding to the 

 epipharyngeal plate, is developed, at the entrance to pharynx, a pair 

 of rather large, round, smooth, partly coalescent liypopharyngeal 

 plates. Hypo- and Epipharyngeal Rods {hr and er) are present 

 along the longitudinal margins respectively of hypo- and epi- 

 pharynx; they fuse on each side at the entrance to pharynx into a 

 simple rod; this follows the pharynx for a short distance, but soon 

 separates as a free structure which continues through the interior of 

 the head and attaches posteriorly to the innerside of frons. 



The Tentorium (tea) is poorly developed as a pair of slightly 

 chitinized, blade-shaped rods, originating from the gular margin of 

 hypostoma and ending anteriorly as a thin membrane, attached to 

 the innerside of frons near the antennae. A tentorial cross bridge 

 and a pair of posterior prolongations lack, or are possibly represented 

 by a peculiar trifurcate formation (tb) attached interiorly to the 

 posterior end of the gular plate. 



The Prothorax (Pr). — Notches {=:Nodi). — No distinct notches 

 occur in the cervical membrane except a pleural notch at the upper 

 corner of the hypopleural chitizination (ph), but posteriorly, in 

 the intersegmental membra !!0 between pro- and meso-thorax, are de- 

 veloped a dorsal notch (dn) rather close to the dorsal middle line of 

 the body, a lateral notch (In), a pleural notch (pn) just behind the 

 lateral notch, a ventral notch (vn) interiorly dcA^eloped into a spine, 

 and finally a sternal notch (sn) in front of the ventral notch and at 

 the end of a median, sternal, chitinous plate. 



Sutures. — The prothoracic dorso-lateral suture is indistinct; but 

 the prothoracic ventro-lateral suture (vl) between the pleural notch 



