94 CALIFORNIA ACADEMY OF SCIENCES. 



this is a character shaped hke a horse shoe, and consist- 

 ing of a series of horny teeth, shining black in color. 

 The lateral series may be described as containing nine 

 well formed, conical teeth, and the middle series con- 

 sisting of three horny pieces, the one in front conical, 

 the two behind elongate; there are also two independent 

 pieces on either side. These four pieces last referred to 

 are all black and horny in texture but are not in high 

 rehef like the teeth. Fig. IV represents the hypo- 

 pharynx and basal joints of the labium. The char- 

 acters here are almost a repetition of those found in the 

 epipharynx but they are more robust. They present a 

 great resemblance to the upper and lower jaws of the 

 vertebrata, the vertical movement of the labrum and 

 labium makes the likeness complete, the single tootl 

 in each of these parts standing in the position of an in- 

 cisior tooth, and no doubt performing incisors work, while 

 the lateral series most certainly carry on the functions of 

 molars. The interior organization of the mouth is surely 

 of a high order, for though the mandibles are the true 

 incisors, yet in the interior more dividing is to be done, 

 and if this insect could only be classed with the Urodela?, 

 these teeth would bear the names of vomerine and pala- 

 tine, which they more resemble than ligula and para- 

 glosse. 



THORACIC SEGMENTS. 



I St seg. more than twice as wide as long, front and 

 hind margins parallel; sides boldly rounded in front, ob- 

 tusely behind; sides of the thoracic segments deflexed. 



2nd seg. the narrowest; just behind the front margin 

 is a raised line not parallel. 



3rd seg. wider than the second; has a fine parallel 

 raised line in front and a divided line, not parallel near 



