366 



MR. STANLEY HIHST ON 



' Family LiSTRorHOUiD^. 



LiSTROPHORUS FRONTALIS, Sp. n. (Text-fig. 10 A & B,) 



. (S . Dorsal (frontal) process of capitulum much more strongly 

 salient than in L. argentimcs, being fairly long and conical (text- 

 fig. 10 A). Abdominal lobes rather shorter than in L. argentinus, 

 and somewhat differently shaped (text-fig. 10 B). 



$ . Process of capitnlum similar to that in the male. 

 Length, S 330-345 /x, $ 365 /x. 



Habitat. Pai"asitic on the rodent Orizomys delticola, from Isla 

 Ella del Delta, Pai-ana. 



Text-figure 10. 



A. Anterior end of Listrophorus frontalis. B. Posterior end of abdomen of male of 

 the same species. G. knievior ewdi oi Ziistropliorus argentinus. U. Posterior 

 end of abdomen of male of this mite. 



Listrophorus argentinus, sp. n. (Text-fig. 10 C & D.) 



S . Dorsal (frontal) process wider than long and rounded in 

 outline (text-fig. 10 C). Abdominal lobes ending in a delicate, 

 almost truncate process, the posterior edge being, however, 

 slightly oblique ; the gap between the tw^o lobes long and 

 narrow (text-fig. 10 D). 



$ . Capitulum of female very like that of the male. 



Length, 6 345-360 /x, $ 415-450 /x. 



Habitat. Argentina; on a rodent {Scapteromys tonientosus) . 



Trich(ECIus brevipes Can. & Trt. 



According to Canestrini and Kramer in ' Das Tierreich ' (Sar- 

 coptidtB, etc.), this interesting little Listrophorid mite has only 

 been found in Thessaly, and I cannot find a later reference to the 

 species. As a matter of fact, it is not uncommon on English 

 rodents. I have collected numerous specimens off Evotomys 

 glareolns britannicus at Exeter, and ofi' Microtus agrestis at 

 Barnes, Siirrey. 



