498 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Maxillw rather stout. Cardo and stipes rather distantly sepa- 

 rated from the mentuni by a membranous structure. Palpi three- 

 jointed, second joint slightly broader than the first, third distinctly 

 smaller. 



Mentuni subquadrate, sides slightly converging to base, apex sin- 

 uato-truncate, the articulating meml)rane attaching it to the pal- 

 piger more or less distinct; ligula a delicate median process between 

 the palpi, bearing two setae at tip. 



Lahlal palpi short and two-jointed; first joint about as wide as 

 long, possibly a little longer if fully extended; second joint nnich 

 narrower and smaller. 



Suhmentum (figs. 8*' and lis-, Plate 13) trapezoidal, base moderately 

 arcuate, apex truncate, sides feebly, broadly but distinctly sinuate. 

 Both the mentum and submentum are sparseh^ clothed Avith rather 

 long flying hairs. 



Gula subquadrate, sides somewhat arcuate basally and feebly sin- 

 uate apicall3\ Suture distinct. 



Lahnnn transverse, a little more than twice as wide as long, anterior 

 margin slightly arcuate, more strongly rounded laterall}^ There is 

 an apical series of about eight setse, and a basal series ai)parently the 

 same in number. 



Clypeus with a feebly transverse impression which shows at the 

 sides as an emargination. just back of which is a setigerous puncture, 

 another more internal, the setic of the two sides being in line; sepa- 

 rated from the frons l)y a distinct transverse groove which ter- 

 minates at the anterior border of the antennal socket. 



Prothorax nearly quadrate on the dorsum. slightW transverse, in 

 some specimens transversely and feebly concave. Meso- and meta- 

 thornx nnich shorter and together scarcely as long as the prothorax. 



Ahdoniinal segments subequal in length. 



Spiracles. — There are nine pairs. The anterior is situated under 

 the margin of the prothorax in a depi'ession external to the coxa, 

 larger than the otiiers and with the margins more })rominent and 

 chitinous. Tlie abdominal are in segments 1-8 inclusive and situated 

 at the anterior margin of the [)leurites: they are circular and flat, 

 margins not pi-ominent. 



Pygidium (Plate 13, fig. 5) triangular, sides moderately arcuate, 

 apex rather broadly rounded. The marginal series of sjiines con- 

 sists of eight on each side, the terminal two are just noticeably a 

 little stouter and longer than the others. 



The sjiecimen from which fig. 5 was drawn shows three spines dis- 

 placed inward from the j^roximal extremity of the marginal series; 

 another specimen had them present only on one side and in others 

 they were entirely absent. I was unable to determine if this was the 

 result of wear. 



