120 



STANLEY HIRST — ON THREE NEW SPECIES 



Genus Dermanyssus. 



Subgenus Liponyssoides, nov. 



Capitulum somewhat longer and narrower than is the case in the typical 

 species of Dermanyssus. Chelicera of male furnished with a long accessory 

 process (Hagellum) which is armed with a little tooth. 



Dermanyssus (Liponyssoides) muris, sp. n. (figs. 1-2). 



Q. Body rather long oval, but its exact shape varies considerably, for it is 

 sometimes much swollen with ingested blood. Scutum long and rather narrow, 

 leaving much of the dorsal surface uncovered ; it is wedge-shaped, being 

 gradually and progressively narrowed posteriorly ; the posterior end is very 

 slightly rounded (almost truncate). A number of fine hairs, of moderate length, 

 are present on its surface ; for the greater part of the length of the scutum these 

 hairs are mostly arranged in transverse series o£ four or six hairs or in pairs ; on 



Fig. 1. — Dermanyssus {Liponyssoides) muris, Hirst, dorsal view of female. 



the posterior part of the scutum there are only pairs of hairs. Sternal plate 

 trapezoidal in shape, and furnished with three long fine hairs on each side. The 

 plate which is situated behind the genital operculum is long, narrow and wedge- 

 shaped, gradually diminishing in width posteriorly, its end being blunt ; there is 

 a pair of rather long fine hairs on this plate and they are placed opposite the 

 fourth coxa. Anal plate heart-shaped and furnished with the usual three hairs, 

 which are rather long and fine ; posterior margin of this plate punctured in a 

 striate fashion. Peritreme long, extending as far forwards as the coxa of the 

 second leg or slightly beyond it. Some distance in front of the anterior end of 

 the peritreme, there is present (at least in the specimens from Colombo) a little 

 round eye-like structure, but owing to its position it is very difficult to see. 



