ON NEW OR LITTLE-KNOWN ACARI. 365 



LlPONYSSUS SERPENTIUM Hirst. 



This species was described from examples found on a Couper's 

 Snake at the Society's Gardens. I have examined some additional 

 specimens from the Horned Viper (Vipera cerastes), also from 

 our Gardens. The first-named host is a Mexican species, whilst 

 the latter is a North African form. This mite has also been 

 found on snakes that have died at the Bronx Zoological Park, 

 N.Y. It is believed that this parasite was introduced with the 

 Malayan Python {Python reticulatus), and, whilst it does not 

 harm that host, may leave it and attack American snakes of any 

 kind, giving rise to a kind of blister or eruption under the edge 

 of the scale, causing death. According to Mr. Ditmars, several 

 snakes have been lost from this cause. The above details, relating 

 to the American case, are taken from Mr. P. S. Falshaw's letter 

 accompanying the specimens. 



Liponyssus serpentium is easily distinguished from the allied 

 L. natricis by the presence of two dorsal shields instead of only 

 one. The genito- ventral plate is ornamented with longitudinal 

 linear markings, as in L. natricis. 



Liponyssus arabicus, sp. n. 



5 . There are two plates on the dorsum in this species, the 

 posterior being very minute and oval as in L. serpentium mihi, 

 but the anterior one is long and wedgecl-shaped, reaching far 

 backwards, and only separated from the minute posterior plate 

 by a comparatively short space (whereas in L. serpentium the two 

 plates are widely separated from one another). Anterior plate 

 furnished with a number of hairs. The minute posterior plate 

 does not bear any hairs. Hairs of body lacking minute off-shoot 

 present in L. bacoti mihi. The minute platelets present between 

 the main shields in L. serpentium appear to be absent in the 

 new species. Besides the usual fine striatums of the integument, 

 there are a number of fairly long, but very fine chitinous (?) 

 linear markings, especially numerous at the sides of the body. 

 Venter. Sternal shield trapezoidal in shape, and with two pairs 

 of hairs on its surface. Genito-ventral shield long and narrow. 

 Anal plate pear-shaped ; the paired hairs on it shorter than the 

 unpaired one. Legs. Coxa? without spurs ; the other segments 

 with the usual fairly stiff hairs, but without any strong spines. 



Length '73 mm. 



Habitat. A single specimen from a lizard (A gaona adramitana) ; 

 Acl Dthala, Upper Hushabi, South Arabia. 



Liponyssus bursa Berlese. 



During a recent visit to the Natural History Museum, Mr. M. 

 Koidzumi brought me two specimens of a mite found on a 

 Chinese patient at HokoTo Island, Formosa. They are referable 

 to the tropical fowl-mite (Liponyssus bursa Berlese). 



25* 



