IBT. 20. . STUDIES OF THE BITING LICE EWING. 17 



Tarsal claw slightly curved and with inner margin irregularly ser- 

 rate toward the base. 



Length of male, 1.81 mm. ; width, 0.58 mm. 



Type host and type locality. — Gtenomajs osgoodi from near head 

 of Rio Chico, Santa Cruz, Argentina. 



Tyjye slide.— Cut. No. 23749, U.S.N.M. 



Described from a single specimen, the holotype, which is a male. 

 This species differs from G. forficulatns in a number of characters, 

 the more important of which are : The more slender body, the shorter 

 and differently shaped tarsal thumb, the large palpi, and various 

 differences in the genital armature of the male. 



GYROPUS LATIPOLLICARIS, new species. 



Plate 1, fig. 4. 



Similar to G. pollicaris, but differing only in a few minor details. 

 Temporal angles rather sharp; antennae large and in the case of 

 female specimens frequently with the last two segments aborted or 

 broken off; palpi rather large and with the four segments very pro- 

 nounced. Prothorax with anterior margin almost straight, sides 

 about straight and subparallel for a part of their length, then strongly 

 converging to the posterior end of the segment. Mesothorax about 

 twice as broad as long and with sides slightly diverging posteriorly. 

 Metathorax scarcely as large as prothorax and with sides strongly 

 divergent posteriorly. Abdomen fully twice as long as broad and 

 sometimes more than twice as long. Gonopods of female vestigial but 

 provided with the usual fringe of long setae. Male genital armature 

 compact, conspicuous, and with large basal plate, the sides of which 

 diverge slightly posteriorly. Legs nearly subequal in female, but in 

 male first pair larger and stouter than the others. . Thumb of tarsus I 

 of male (pi. 1, fig. 4) much swollen and strongly curved and bearing 

 near its tip three subequal setae. 



Length of female, 2.00 mm.; width, 0.72 mm. Length of male, 

 1.97 mm.; width, 0.63 mm. 



Type host and type locality. — Otenomys osgoodi fro.m Rio Chico, 

 Santa Cruz, Argentina. 



Type slide.— Cat No. 23750, U.S.N.M. 



Described from three females and three males on a male skin of 

 Otenomys osgoodi (Cat. No. 84160, U.S.N.M.) from Rio Chico. 

 Santa Cruz, Argentina, and two males found on a female skin of 

 Otenomys osgoodi (Cat. No. 84165, U.S.N.M.) from Pacific slope, 

 Chile, near head of Rio Chico, Santa Cruz, Argentina. It would 

 hardly seem that two species so nearly related as 0. poUicaris and 

 O. Utipollicaris should exist together on the same host, yet the 

 differences in the tarsal thumb of the males are accompanied by 

 several differences in the male genitalia of the two forms. 



