132 KANSAS UNIVERSITY SCIENCE BULLETIN. 



to the inner surface of the frons. At its distal end the pharynx 

 fuses with the hypopharynx and hypopharyngeal lamellae. The 

 organ is heavily chitinized and thick-walled for some distance, 

 but soon becomes narrower and, losing its chitinization, pro- 

 ceeds caudad until about the middle of the back part of the 

 head, where it turns abruptly caudad and enters the thorax 

 to become the oesophagus. 



Mandibles and Maxillse. — In dissecting the mouth parts the 

 labium is generally torn loose from its connection below the 

 hypopharynx and other parts and left connected to the thorax, 

 as already mentioned. The setae, however, remain fixed firmly 

 to the upper parts of the mouth {32-1) and can be sepa- 

 rated and torn loose from these parts only with difficulty. They 

 are held together by the labrum and epipharynx above, the 

 maxillary sclerites and maxillary processes on the sides, and 

 by the hypopharynx below. From this point the bases of the 

 mandibles and maxillae diverge cephalad and laterad in a man- 

 ner which has aptly been compared to the form of the letter 

 "Y." The orientation of these parts was best seen in either a 

 lateral view of the frons, clypeus and other parts removed 

 from the head, or by examining the parts in such a position 

 as to look down on the bases of the setae in the direction of 

 their distal ends. In such a position this divergence, which 

 takes place immediately cephalad of the hypopharynx and 

 other closely enveloping parts, can be plainly seen. The bases 

 of these setae {26-%, 9) are hollow, funnel-shaped, heavily 

 chitinized, and attached to the other parts by tendons and 

 muscles. One pair of these setae, from their cephalic posi- 

 tion, were recognized as the mandibles, and when dissected 

 out were found to surround the other pair of stylets through- 

 out their entire length, their slightly concave inner surfaces 

 fitting closely against them. This latter, inner pair represents 

 the maxillae. On dissection they were found to be held firmly 

 between the mandibles on each side and were difficult to sep- 

 arate. The mandibles are thicker than the maxillae, but not so 

 wide. Their relative shapes can be seen in cross section in 

 31-^. As in the cicada, the setae shortly after leaving the 

 head begin to curve so that the mandibles are above and below 

 the maxillae instead of laterad of them. This curving was seen 

 in sections distad of the bend of the labium and had begun in 

 the section from which figure 5 was drav^ni. In this figure the 



