MILLIPEDS OF MEXICO AND CENTRAL AMERICA 11 



16. Gonopod coxa without solenite; telopodite with large oval or elon- 



gate cavity in mesal face containing many setae. 



RHACHODESMIDAE 



Gonopod coxa with solenite which projects into a narrow groove at 



base of telopodite 17 



17. Usually broad, compact forms, the W/L ratio usually 18% or greater, 



body widest near middle in males, near caudal end in females; 

 sensory cones of antennae not separated or paired; 6th antennal 

 joint without an external sensory pit; solenite of gonopod coxa 

 originating from a circular socket well removed from distal edge 

 of coxa; prefemora of walking legs normally with acute distal 



spine XYSTODESMIDAE 



Narrower forms, typically with reduced and well-separated keels, the 

 W/L ratio usually 18/c or less, body usually widest near head in 

 both sexes; sensory cones of antennae usually separated into two 

 pairs in larger forms; 6th joint with a prominent external distal 

 sensory pit; solenite of gonopod coxa located in a notch on distal 

 edge of coxa; prefemora of walking legs normally without acute 

 spines CHELODESMIDAE 



Family CHELODESMIDAE 



Genus ALOCODESMUS Silvestri 1896a, p. 5. 



TYPE SPECIES: Alocodesmus angustatus Silvestri, by monotypy. 

 Alocodesmus angustatus Silvestri 1896a, p. 5. 



Alocodesmus dromeus Chamberlin 1922, p. 48; Loomis 1964a, p. 16. 



TYPE: Torino Mus. 



TYPE LOCALITY: Given as Darien, but Carl 1914, p. 897, says the 

 holotype came from Punta Sabana. Darien Prov., Panama. 

 Alocodesmus silvestri (Attems). 



Leptodesmus (Desmoleptus) silvestri Attems 1931, p. 23; Loomis 

 1964a, p. 130. 



TYPE: Male and female syntypes in Naturh. Mus. Wien. (H) 



TYPE LOCALITY: Panama. 



Genus ATYLOPHOR Chamberlin 1922, p. 49. 



TYPE SPECIES: Atylophor rafaelanus Chamberlin, by original desig- 

 nation. 

 Atylophor rafaelanus Chamberlin 1922, p. 50. 



TYPE: U.S. Nat. Mus., no. 849. 



TYPE LOCALITY: San Rafael, Guatemala. There are two localities 

 by this name, the smaller is about 15 km. west of Guatemala City, the 

 other about 30 km. southwest of Jalapa, and it is not known which is the 

 type locality. 



273-687 O - 68 - 2 



