381 



A Contribution to the Life History of Ixodes redufius (Linn.). 

 By R T. Lewis, F.R.M.S. 



{ReadJune loth, 1900.) 

 Plate 21. 



Readers of " Science Gossip " will remember that during 1899 * 

 a series of papers appeared frpm the pen of Mr. E. G. Wheler, 

 of Aln^vick, a member of this Club, entitled " Ticks and Louping 

 111," in which the writer described the serious damage done by 

 a disease amongst sheep, locally known under this name. Mr. 

 Wheler subsequently communicated to the Royal Agricultural 

 Society a more extended account of the observations made ; this 

 was published in the Journal of that Society, vol. x., part iv., 1899, 

 and has since been reprinted for private circulation. 



The species of tick held responsible for conveying the infection 

 to the sheep, has been satisfactorily identified as Ixodes reduvius 

 (Linn.). The determination of species in the case of ticks is, 

 however, not so easy a matter as may at first be supposed, since 

 individuals of the same species, especially the females, are found 

 to vary in a remarkable degree as to size and colour, according to 

 their age or condition as regards feeding, or repletion with, ova, 

 whilst the males often differ from the females in a still more 

 marked degree. It is not therefore surprising to find on reference 

 to Neumann's recent work, " Revision de la Famille des Ixodides,"t 

 that his description of Ixodes reduvius is headed with a list of 

 nineteen synonyms, under which this same creature appears to 

 have been known to different writers. 



Mr. Wheler's chief object in taking up the subject was to 

 ascertain by what means the disease referred to might be success- 

 fully combated. As it appeared certain that these ticks were 

 active agents in communicating the disease to the sheep, his first 

 endeavour was to make himself acquainted as far as possible with 

 their life history, and the exceptional opportvmities which he enjoys 

 for obtaining living specimens and studying them in their native 

 habitat have been taken advantage of with excellent results. It 

 is not intended in this paper to give any special description either 

 of the ticks or of the mischief they are charged with doing — this 

 * Vol. V. pp. 5, 46, 108. t Part 3, p. 112. 



