ART. 20. STUDIES OF THE BITING LICE — EWING. 27 



No. 12095, U.S.N.M. of Pccari angtdahifi crusnigrum from Tala- 

 manca, Costa Rica. 1874, by W. M. Gabb. 



A further study of the lice of the peccaries is much to be desired. 

 Nits of what is evidently an undescribed species of Macrogi/ropus 

 occur on a skin of the Costa Rican white-lipped peccary {Tayassu 

 pecari spiradens) in the United States National Museum. 



HETEROGYROPUS, new genus. 



Head very broad, about twice as broad as prothorax, and with 

 deep antennal fossae. Tarsus I provided with two claws. 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 transversely furrowed and with the claw 

 proper, which is greatly reduced, forming a clawlike structure adapt- 

 ed 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, typically each segment with one trans- 

 verse row of setae. Sexual dimorphism probably wanting. 



Genotype and its host species. — Heterogyropus heteronychus., new 

 species, from Kerodon spixii. 



This genus, with its single species, is of particular interest as it 

 probably bridges over the gap between the one-clawed and two- 

 clawed mammal infesting Atnblycera; however, the accessory claw 

 may not prove to be a real tarsal claw from the standpoint of homol- 

 ogy; or, again, its presence may be due to regression, in which 

 case the genus should not be considered as an intermediate one. 

 In M acrogyropus the accessory claw is quite small, being almost 

 vestigial. 



HETEROGYROPUS HETERONYCHUS, new species. 



Plate 1, fig. 6, and text figs. 2 and 12. 



A medium-sized pale species. Head broader than long; temples 

 projecting, without angles; antennal fossae broad and deep. Last 

 two segments gone from both of antennae. Palpi with the four 

 segments quite distinct, last segment about one and a half times as 

 long as broad and reaching to the anterior margin of the labrum. 

 Dorsally the head is sparsely clothed with small setae, many of which 

 are arranged into a transverse row across the temporal region: 

 two large setae are situated on each lateral margin of temples. Pro- 

 thorax somewhat over one-half as broad as the head, about twice as 

 broad as long and with sides rounded; mesothorax much broader 

 than prothorax but scarcely as broad as the head: metathorax as 

 long as mesothorax and slightly broader. Abdomen oval, about one 

 and a half times as long as broad; each segment, except the last 

 one, bears above a transverse row of short setae situated almost on 



