20 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 68. 



There is at hand also a lot from the same place by the same collector 

 consisting of three females and one nymph taken on a male skin of 

 Ctenomys, species (Cat. No. 236335, U.S.N.M.: Biol. Surv. Collec- 

 tion) , April 9, 1921. 



ALLOGYROPUS, new genus. 



Head broad; antennal grooves not so broad as in other genera. 

 Tarsus I provided with a single claw. Femur II and III each pro- 

 vided with a forked and furrowed 

 tenaculum for holding tarsus. Tar- 

 sus II and III each with second seg- 

 ment greatly elongated and trans- 

 versely furrowed and with the claw 

 proper, which is gi'eatly reduced, 

 forming a clawlike structure adapt- 

 ed for fitting into femoral tenacu- 

 lum. Tibia I without a row or tooth- 

 like setae on a swollen or thumblike 

 expansion at the inner distal margin. 

 Abdomen oval, typically each seg- 

 ment with one transverse row of 

 setae. Sexual dimorphism slight or 

 wanting. 



Genotype and its host species. — 

 Gyropus amplexans Neumann from 

 Dasyprocta aguti. 



The following species are included 

 in this genus: G. amplexans Neu- 

 mann, G. setosus (Neumann), and 

 G. turhinatus (Piaget) . The separa- 

 tion of the species which have but a 

 single transverse row of dorsal setae 

 to each abdominal segment from the 

 others of the genus Gyropus has its 

 justification, it is believed, in its analogy to the similar process by 

 which certain genera of sucking lice are separated. Unfortunately 

 the writer has never encountered any of the species of this genus. 

 Neumann (1912) has separated them as follows in his key: 



a.* Abdomen with hairs find setae very unequal A. setosus (Neumann;. 



a.' Abdomen with hairs and setae equal. 



6.^ Abdomen with rows of setae short, interrupted on the median line and 

 toward the sides. Head much broader than long. 



A. turbinatus (Piaget). 



&.' Abdomen with rows of very short setae across the whole width of the 



segment. Head scarcely broader than long_-A. amplexans (Neumann). 



Fig. 9. — Gyropus wetmorei. 

 plates of female. 



Sternal 



