6 PROCEEDINGS OF THE NATIONAL MUSEUM, vol.65. 



of setae on each segment, beginning with the proximal one, is 

 7, 9, 2, 3. 



The rrumdible {?nd, fig. 8) is on the cephalo-lateral aspect of the 

 head, cephalad of the antenna, and projects dorso-cephalad at an 

 angle of about 45°. It is sickle-shaped (fig. 32) with a prominent, 

 pointed tooth on the mesal margin about one-third the distance from 

 the base. Opposite this tooth on the outer margin are four stout 

 setae and at the })ase are several smaller ones. On its dorsal aspect 

 at the base is a projection with an acetabulum which articulates 

 with the knob-like projection of the anterior arm of the tentorium. 

 On the ventral aspect of the mandible is a prominent condyle which 

 articulates in an acetabulum on the postgenae. 



The maxilla {ma^, fig. 14) is somewhat flattened and is attached 

 to the cephalic margin of the hypostoma. The cardo (ca, figs. 27 

 and 28) consists of two pieces. One part is on the ventral aspect, 

 is somewhat triangular in shape, and bears a prominent setae at its 

 distal point. This sclerite articulates with the hypostoma laterad 

 of the attachment of the labium. The other part of the cardo is on 

 the mesal and dorsal aspects of the maxilla, is strap-shaped, and 

 articulates with the postgena adjacent to the point of attachment 

 of the postgena with the clypeus. The stipes {sfi, figs. 27 and 28) 

 is the large, somewhat flattened and rectangular segment distad of 

 the cardo. On its mesal margin at the base are four or five short, 

 stout setae or spines. In the membrane at the distal end of the stipes 

 is a small sclerite bearing three setae, possibly a rudiment of lucinia. 

 The galea {ga, figs. 27 and 28) is the two segmented mesal appendage 

 distad of the stipes. The proximal segment is about one-third 

 longer than the distal segment. It bears three stout setae on its 

 mesal margin and the distal segment bears five setae. The palpifer 

 {pf, figs. 27 and 28) is laterad of the proximal segment of the galea 

 and separated from it by a suture. It is subequal in length to the 

 palpus and bears one seta on the ventral aspect and six on the 

 dorsal. The palpus {pa, figs. 27 and 28) is the three-segmented ap- 

 pendage attached to the distal end of the palpifer. The proximal 

 segment is the shortest and each succeeding segment slightly longer. 

 The second segment bears two setae on the dorsal aspect and one on 

 the ventral aspect. 



The labium {I, figs. 14, IT, and 21) is attached by a membranous 

 area to the cephalic end of the hypostoma. This membranous area 

 probably represents the mentwn and suhmentum.. Its membranous 

 nature allows of considerable movement of the labium. The fused 

 labio-stipites (Is, fig. 17) is the chitinized area on the ventral surface 

 of the labium. This sclerite has a deep furrow along the meson and 

 extends cephalad as a triangular projection between the palpigers, 

 with a long, stout seta on each side of the furrow. The palpiger 



