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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 63, 



a little more than half of a sphere, which is completed by the dilated 

 part of segment III. Palpi moderate, last segment almost twice as 

 long as next to last. Prothorax about three-fourths as broad as head^ 

 much broader than long and irregular in outline. Mesothorax 

 shorter and narrower than the prothorax and representing the nar- 

 rowest region of the body. Metathorax about as long as pro- and 

 mesothorax combined, shaped like a truncated cone. Abdomen 



slightly swollen and moderately well 

 clothed with flattened setae. Male 

 genital armature (fig. 5) conspicuous; 

 basal plate, long and pedicel-like; 

 parameres (?). From near the apex 

 of basal plate arise four pairs of very 

 long, slender, curved seta -like struc- 

 tures which extend beyond the margin 

 of the armature proper. Three pairs of 

 legs differing as they do in the genus. 

 Tibia II strongly arched on the out- 

 side and broadest at its middle; tibia 

 III similar to tibia I, being broadest 

 at its distal end. Tarsal claw I almost 

 straight and sharp at its apex; tarsal 

 claw II exceedingly short and minute, 

 but very sharp; tarsal claw III fully 

 twice as long as two, slender, but 

 slightly curved, and also exceedingly 

 sharp. Femoral tenaculum moderate 

 but with a very deep fork, or crotch. 

 Length, 1.29 mm. ; width, 0.43 mm. 

 Type host mid type locality. — Gte- 

 noviys colburni from Huanuluan, Rio 

 Negro, Argentina. 



Type slide. — Cat. No. 23748, 

 U.S.N.M. 



Description based on the type, a 

 male specimen from a female skin of 

 rtenomys rolhnrni (Cat. No. 238122, 

 U.S.N.M.) taken from Huanuluan, Rio Negro, Argentina. Another 

 male specimen, taken from a skin of Ctenomys sericeus, male (Cat. 

 No. 84192, U.8.N.M.), collected at Rio Chico, Santa Cruz, Argentina, 

 appears to differ in no specific respect from the type. 



Genus GYROPUS Nitzsch. 



Fig. 5. — M onogyropds parvds. 



COPDLATORY AITARATUS OF MALE. 



Head broad and very deeply notched in front -of temples. Tarsus I 

 provided with a single claw. Femur II and III each provided with 



