Chilton. — Species of Ixodes parasitic on the Grey Duck. 201 



Art. XXIV. — A Species of Ixodes parasitic on the Grey Duck. 



By Chas. Chilton, M.A., D.Sc, F.L.S., Professor of Biology, 



Canterbury College. 



[Read before the Philosophical Institute of Canterbury, 4th November, 



1903.] 

 Plate X. 



In May, 1903, Mr. W. W. Smith, of Ashburton, sent me 

 some specimens of a " tick " found on a specimen of the grey 

 duck (An.as superciliosa), with the request that I would ex- 

 amine them, and describe them, if necessary. 



The specimens forwarded appear to belong to the genus 

 Ixodes, Latreille, of which five species have been already 

 described as parasitic on various New Zealand birds. Of 

 these three were described by the late "W. M. Maskell — viz., 

 I. eudyptidis, from a penguin ;■•' I. apteridis, parasitic on the 

 North Island kiwi [Apteryx manteUi);\ and I. ajjtericola, found 

 on the South. Isl&nd kiwi {Apteryx australis). I Mr. T. W. Kirk 

 has described one species, I. viaskellii, obtained from young 

 specimens of the pencilled albatros, and has also recorded the 

 fact that he found on a large gull a tick exactly similar to the 

 one from the crested penguin described by Mr. Maskell. § A fifth 

 species has been more recently described by M. Neumann in 

 a paper wiiich I have had no opportunity of consulting. || 

 I have been unable to identify my specimens with any of the 

 others described from New Zealand, and have therefore 

 ventured to describe them as new. I do so, however, with 

 considerable hesitation, as I have not specially studied the 

 group. I hope, however, that the description and figures 

 given below will be sufficient for future identification. In the 

 general shape and markings on the body the species here 

 described seems to rather closely resemble Ixodes 7naskellii, 

 T. W. Kirk, but in the absence of figures of that species I 

 have not ventured to refer my specimens to his species. 



Ixodes anatis, sp. nov. Plate X., figs. 1 to 6. 



Female. — Body broadly elliptical, slightly constricted at 

 the sides ; cephalic shield lighter in colour than rest of 

 body, very small, oval, narrowing in front, only partially 

 visible in dorsal view. On dorsal surface two shallow 

 grooves or markings extend backwards and outwards from 

 the cephalic shield, and lead to two irregular depressions 

 situated about one-third the length of the body from the an- 

 terior end ; from these depressions extend two well-marked 

 lateral grooves, curving slightly inwards and reaching nearly 



* Trans. N.Z. Inst., xvii., p. 19. f L.c, xxix., p. 291. J L.c, xxix., 

 p. 29 . § L.c, xix., p. 65. |! Mem. Soc. Zool. France, 1899, p. 132. 



