ART. 20. STUDIES OF THE BITING LICE EWING. 21 



TETRAGYROPUS, new genus. 



Head broad; temples broad and somewhat squarish. Tarsus I 

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

 a forked and furrowed tenaculum for holding tarsus. Tarsus II 

 and III each with second segment greatly elongated and trans- 

 versely furrowed and with the claw proper, which is greatly reduced, 

 forming a clawlike structure adapted for fitting into femoral 

 tenaculum. Tibia I without a row of toothlike setae on a swollen or 

 thumblike expansion at the inner distal margin. Abdomen oval, 

 tj'pically each segment without any transverse row of setae, the 

 latter being arranged so as to form at least four longitudinal rows. 

 Sexual dimorphism slight or wanting. 



Genotype and its host species. — Gyropus lineatus Neumann fron\ 

 Kerodon moco. 



Three species are for the present placed in this genus, but further 

 study may necessitate the erection of a new genus for one of them 

 which comes from a primate host. Contained species: T. lineatus 

 (Neumann) and two species to be described in this paper. 



KEY TO THE SPECIES OF TETRAGYROPITS. 



0.' Mesothorax about equal in width' to the prothorax ; hist segment of antenna 

 longer than broad ; tubercle of femoral tenaculum rounded. 

 &.* Accessory tubercle of femoral tenaculum large and conspicuous; seg- 

 ments three and four of abdomen without any long hitertil setae. 



T. lineatus (Neumann). 

 6.° Accessory tubercle of femoral tenaculum small ; segments three and 

 four of abdomen each with a pair of long lateral setae. 



T. setifer, new species. 



a." Mesothorax much broader than prothorax; tubercle of femoral tenaculum 



very large, conspicuous and angulate T. aotophilus, new species. 



TETRAGYROPUS LINEATUS (Neumann). 



Head slightly broader than long; temporal lobes rounded, prac- 

 tically without angles; antenna] fossae deep, posterior wall striate, 

 inner margin of each fossa doubly emarginate hence somewhat E- 

 shaped. Palpi almost reaching the anterior margin of labrum. 

 Prothorax almost as broad as head, with sides strongly convergent 

 posteriorly. Mesothorax about equal to prothorax in width and 

 length but differently shaped. Metathorax broader than mesothorax 

 and similarly shaped. Abdomen about twice as long as broad and 

 %vith four longitudinal rows of straight setae, each seta extending 

 to the base of succeeding seta, thus making four continuous lines 

 across the abdomen. Long lateral setae, much longer than the dorsal 

 setae, are on segments Y, VI, and VII. Gonopods low and each witli 

 5596— 24— Pr. sc.N. M.vol.aS— 37 



