1922] Chamherlin — A New Chilopod from Mexico 9 



A NEW SCHENDYLOID CHILOPOD FROM MEXICO. 



By Ralph V. Chamberlin, 



Museum of Comparative Zoology, Cambridge, Mass. 



The type of the interesting new chilopod described below was 

 taken by Dr. Wm. M. Mann several years ago at Guerrero Mill, 

 Hidalgo, Mexico. It represents a new genus related to the 

 North American genera Nyctunguis Chamberlin and Nesonyx 

 Chamberlin in having ventral pore areas in the anterior region 

 and in possessing a well developed claw on each anal leg. It 

 differs from these genera in having only a single coxal pore on each 

 side. In this respect it agrees with the West African Mesos- 

 chendyla of Attems, but the latter genus has no claw on the anal 

 legs. 



Mexiconyx, Gen. nov. 



Claw of the second maxillse pectinate. Labrum with median 

 arc bearing true teeth which are well chitinized and have dis- 

 tinct roots. Mandible with a single pectinate lamella. Ventral 

 pores present on sternites of the anterior region. A single coxal 

 pore on each side, this simple or homogeneous. Anal legs 

 terminating in a normal claw. 

 Genotype. — M. hidalgoensis, sp. nov. 



Mexiconyx hidalgoensis, sp. nov. 

 Head longer than wide, widest in front of middle; anterior 

 margin convex or very obtusely subangular, the caudal margin 

 straight and the lateral margins convex and converging caudad 

 from in front of middle. Prebasal plate not exposed, the head 

 well overlapping the basal plate, the exposed portion of which is 

 rather short. Claws of prehensors when closed surpassing the 

 head, reaching to the end of the second antennal article or nearly 

 so. Joints of the prehensors unarmed within. Prosternum also 

 unarmed; without chitinous lines. Labrum rather deeply ex- 

 cavated at the middle and bearing in the type twenty-two 

 teeth of which those of the median arc are more strongly chitinized 

 and differentiated; five teeth at the crest of the arc are directed 

 ventrad. Dentate lamella of mandible presenting six or seven 



