NEW TAliASlTK! !S[1TES. 775 



Sterual plate with three pairs of hairs 22. 



21.^ 



. Sternal plate with two pairs of hairs 23. 



Dorsal sliield iKivrow, e.spocially posteriorly (parasitic 



on rats) L. bacoti Hirst. 



Dorsal sliield wider (parasitic on hen) L. buj-sa Berlese. 



rHairs on dorsum onl}' slightly curved X. silmarum 



23. •] Can. & Fanz. 



(^ Hairs on dorsum very distinctly curved 24. 



r Dorsal shield rather short. Anal plate rather wide 



1 and short L. lacertimis Berlese. 



24 W 



! Dorsal shield more elongated. Aual plate narrower 



1^ and longer L. saurat'iim Ondmns. 



LiPONYSSus NATRicis Gerv. 



L'vponyssus arabicus milii described from a female specimen 

 found on a lizard (Agama adramitana) is appareiitly identical 

 with i. natricis Gerv. I have examined examples of the latter 

 found on a snake at Florence kindly sent me by Prof. Berlese. 

 A very minute posterior shield is present on the dorsum in the 

 adult female, and Berlese seems to have overlooked it. It is 

 very similar in shape to tha.t present in L. serpentium mihi, but 

 is longer and only separated from the anterior dorsal shield by a 

 short space, whereas in the L. serpentium the two dorsal shields 

 are widely separated from one another. 



LiPONYSsus VIATOR, sp. n. (Text-fig. 20.) 



2 . There are two dorsal shields, shaped as shown in figure, 

 the anterior one being slightly produced in the middle posteriorly, 

 whilst the posterior one has the anterior margin lather strongly 

 concave ; posterior dorsal shield shaped rather like a tongue, the 

 lateral margins being at first convex and then narrowing to form 

 the bluntly pointed posterior end. Hairs on dorsal shields short, 

 some of the hairs on the margins of the anterior dorsal shield 

 are a little longer, and the hairs of the terminal pair on the 

 posterior shield are longer than the others on its surface. 

 Lateral hairs on body fairly long and the posterior hairs on 

 uncovered part of dorsum very much longer than those on the 

 shields. Sternal plate very short, being in the form of a narrow 

 transverse strip; it bears three pairs of hairs, those of the 

 anterior pair are much shorter than the posterior ones, the latter 

 being much longer than usual. Genito -ventral plate narrov\^, the 

 posterior end rather 'blunt. Anal plate peai"-shaped . Peritreme 

 reaching as far forwards as the middle of the second coxa or 

 somewhat further forwards. A minute and inconspicuous spine 

 or spur is present on the anterior surface of the second coxa, but 

 it is much shorter than in most species of Liponf/ssia ; the other 

 coxsd apparently are without spurs. It is not easy to make out 

 the denticle on the first free segment of the palp in the specimens 



Proc. Zool. Soc. — 1921, No. LII. 52 



