BRITISH HYDRACHNIDiE. 153 



Genus, Axona (Kramer)." 



Body chitinous, with a granulated surface and a depressed line 

 round margin of body. Legs short, not very hairy, but adapted 

 for swimming ; all tarsi have claws. Epimera fused together into 

 one group. Palpi, long. Fourth joint, spoon-shaped ; second 

 joint has a small, peg-like process. Eyes widely separated and 

 near margin of body. On each side of the operculum is a special 

 plate, containing three copulative pores. Mandibles in two dis- 

 tinct portions. 



To illustrate above genus, I give species, A. versicolor. 



Axona versicolor fMiiller, Kramer). 

 1776. — Hydrachna versicolor, Miiller, Zool. Dan. Prodr.^ p. 191, 



N. 2285. 

 1781. — Hydrachna versicolor, Ibid., Hyrachnc^, etc., p. 77, Tab. 



VI., Fig. 6. 

 1793. — Tromhidium versicolor, J. C. Fabricius, E7it. Syst., Tom. II., 



p. 400, N. 9. 

 1805. — Atax versicolor, Ibid., Syst. Atitliatorum, p. 367. 

 1835 — 41. — Arrenurus versicolor, C. L. Koch, Deutschlands Crust., 



etc., N. 13, Figs. 16, 17. 

 1854. — Arrenurus versicolor, Bruzelius, Berkr. 0. Hydrachn. som. 



forck., I. Skane, p. 33. 

 1875. — Axona viridis, Kramer, loc. cit., p. 311, Tab. IX., Fig. 19. 

 1879. — Axona versicolor, Neuman, Sveriges Hydrachnider, p 74, 



Tab. XL, Fig. 2. 



This very beautiful mite has been shifted about from one genus 

 to another several times ; but I hope it has at last found a resting 

 place where placed by P. Kramer in genus Axona. The mites, 

 both male and female, from which the drawings are taken were 

 found in the river at Woking on July 14, 1894. The female is 

 about i/5oth of an inch long; the male a little longer. In colour 

 it predominates in a blue-green, with patches of red and white. 

 The epimera is nearly all (but the actual centre) a very vivid green. 

 The centre is a beautiful pink. Koch gives a figure of both male 

 and female, but different in colour. In the specimens from which 

 * P. Kramer, Beitr. zur Naturgeschich. der Hydrachniden, p. 310, "Axona," 



1875. 

 International Journal of Microscopy and Natural Science. 



Third Series. Vol. V. 



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