Otf NEW Oft LlTTLE-liNOWN ACAttf. 357 



19. On some new or little-known Acari, mostly Parasitic 

 in Habit. By Stanley Hirst, F.Z.S. 



(Submitted for Publication by permission of the Trustees of the British Museum.) 



[Received January 18, 1921 : Read April 5, 1921.] 



(Text-figures 1-15.) 



The present note deals with a miscellaneous series of Mites 

 from various localities, including a number of new Gamasid 

 mites found by Mr. James Waterston in the nasal cavities of 

 Scottish birds, also several new ectoparasites from various sources. 

 Demodex is recorded from several new hosts, viz., deer, long-eared 

 bat, mole, and water-rat, three of the species being regarded as 

 new. An interesting pseudoparasite of flies is also described, 

 and a new English jumping- mite (Speleorchestes). 



Text-figures 1-7 were drawn by Mr. E. J. Engel Terzi, nos. 8-15 

 by Mr. Percy Highley. 



Family Gamasid m. 

 Rhixonyssus caledonicus, sp. n. (Text-fig. 1.) 



$ . Abdomen not elongated. Hairs on venter mostly only 

 slightly thickened at the base, the posterior ones situated just in 

 front of the anus are not dentiform, and there is only one pair 

 in this position. Genito- ventral plate shorter and wider than in 

 R. neglecius and R. waterstoni. Legs of moderate length, those of 

 the first pair apparently sometimes longer than the others. Legs 

 furnished with spinules, but they are minute. Claws of first leg 

 with a distinct short process or denticle dorsally. 



Length -9 2-1 -01 mm. 



Habitat. Nasal cavities of Uria grylle (Black Guillemot), North 

 Mavine, Mainland, Shetland Islands: Gluss Voe (25. ii. 1912), 

 and Gluss Point (17. x. 1912), and Voe, Mainland, Shetland 

 (2. iii. 1912). Specimens collected by James Waterston. 



Rhinonyssus levinseni Tragardh. 



Sommatericola levinseni Tragardh, Monograph arktisch. Acar. 

 in R6mer and Schaudinn's Fauna Arctica, 1905, iv. pp. 28-30, 

 text-figs. 42-47, also pi. i. figs. 1, 3, and 8. 



Triigardh's genus Sommatericola must, I think, be regarded as 

 a synonym of Rhinonyssus Trouessart. Iiis species Sommateri- 

 cola = Rhinonyssus levinseni (from nasal cavities of Sommateria 

 mollissima) seems from his description to be closely allied to R. 

 scoticus, but he depicts more spinules round the anus than are 

 present in that species, and also shows the lateral spines on the 

 palp as much stronger than in R. ivaterstoni. 



