122 STANLEY HIRST — ON THREE NEW SPECIES 



This and the following new species of Dermanyssus are apparently found only 

 on rats, and this is somewhat remarkable, for birds are the normal hosts of all 

 the other species of Dermanyssus hitherto described. Ingested blood was present 

 in both the male and female specimens. 



Dermanyssus (Liponyssoides) aegyptius, sp. n. 



9 . Closely allied to D. {Liponyssoides) muris but differing in the following 

 respects : — Scutum much narrower, the posterior part of it being very much 

 narrowed (almost linear) ; arrangement of hairs on scutum very similar, 

 however, to what it is in D. muris. Sternal plate with only two pairs of hairs, 

 but there is a pair of little plates behind the sternal one, and each of them 

 bears a hair. The plate which is situated behind the genital orifice is sharply 

 pointed at its posterior end. Anal plate quite different in shape from that of 

 D. muris, being long ovate instead of heart-shaped. There is no spur on the 

 anterior surface of the coxa of the second leg. Length of body 1*9 mm. 



Material. I have examined specimens of this species taken on the following 

 hosts — (1) Acomys cahirinus ; over two hundred specimens captured at Assiut 

 (and on the feluccas at that town) ; also at Kous. (2) Mus rattus ; numerous 

 specimens found on this host at Assiut, and a few at Kous. (3) Arvicanthis sp., 

 in houses at Assiut. Also some specimens from El-Weladie ; no host given. 

 It is through the kindness of Dr. C. J. Martin, F.R.S., and Mr. A. W. Bacot of 

 the Lister Institute, that I have had the opportunity of examining these 

 specimens ; they were collected by Dr. Petrie. 



The above description is of a preliminary nature ; the species will be described 

 at greater length and figured in another paper. 



Leiognathus bacoti, sp. n. 



Q . Scutum long and narrow, leaving most of the dorsal surface uncovered ; 

 it is widest at a short distance from the anterior end, diminishing gradually (but 

 not in a very regular manner) in width posteriorly, the terminal part of it being 

 quite narrow. Hairs on the scutum of moderate length, on the anterior half of 

 it they are fairly numerous, but posteriorly they occur only in pairs ; there are 

 six of these pairs of hairs on the posterior half, three of them being placed close 

 together on the margins of the extreme end of it. Sternal plate trapezoidal in 

 shape, and furnished with three pairs of fine and fairly long hairs, those of the 

 posterior pair being situated at the posterior angles. Genital operculum 

 continued posteriorly by the usual plate, which is long, slender and rather 

 sharply pointed at the end ; a pair of hairs is present on this plate, opposite the 

 fourth coxae. Anal plate long and pear-shaped, its posterior end is finely 

 striated ; the usual three hairs are present on this plate. Fingers of cheliccra 

 short and apparently without any teeth. Coxae of legs without any well-marked 

 spurs. Peritreme apparently extending as far forwards as the anterior surface 

 of the first coxa. Length *8 mm. 



Material. Five female specimens found on Mus norvegicus on the feluccas at 

 Assiut (Dr. Petrie). 



This species seems to resemble L. saurarum, Oudemans, somewhat in the 

 narrowness of its scutum, but differs from that species in many other structural 

 details. 



