BRITISH HYDRACHNID^. 299 



a thumb and finger. As an illustration of this genus, we give the 

 following description of A. globator : — 



Arrenurus globator (Miiller). 



1776. — Hydrachna globator. Miiller, Zool. Dan. Prodr., p. 188, 



No. 2242. 

 1 781. — Hydrachna globator. Ibid., Hydrachnse, p. 37, Tab. 2, 



Figs. 1—5. 

 1793. — Trombidium variater. J. C. Fabricius, Ent. Syst., Tom. II., 



p. 403, No. 22. 

 1805. — Atax variater. Ibid., Syst. Antliatorum, p. 369. 

 1835. — Arrenurus globator. C. L. Koch, Deutschlands Crust., 



etc., p. 13, Figs. 22, 23. 

 1854. — Arrenurus globator. Bruzelius Beskr. o. Hydrachn. som. 



Forek. i. Skane, p. 31, Tab. III., Fig. 3. 

 1879. — Neuman Sveriges Hydrachnides, p. 88, Tab. X., Fig. 2. 

 1882. — C. F. George, Science Gossip, XVIII. , p. 272, Figs 194 — 



202. 



Male. — This beautiful mite cannot very well be mistaken for 

 any other form. It has a globular process on the dorsal side of 

 the tail, from which it takes its name. Colour, a light delicate 

 green, wdth brown markings. Eyes, deep crimson. On the fourth 

 joint of the fourth leg is a peculiar development, often, but not 

 always, seen in the males of the species of Arrenurus. This is a 

 very small mite, its length being only 3/iooth of an inch. 



Fetnale. — Almost oval in shape, with indentations on each 

 side. Same colour as the male — pale delicate green, with brown 

 markings. Length, 1/2 5th of an inch, being a little larger than 

 the male. 



This mite is by no means uncommon ; I have found it several 

 times. The two specimens from which the drawings (PI. XV.) 

 were made were found at Snaresbrook on one of the Quekett 

 excursions Sept. 2 9th^ 1894. Having a chitinous epidermis, these 

 mites can easily be mounted in Canada balsam, and if the legs are 

 regularly arranged they make very pretty mounts, the delicate 

 colouring bemg brought out by the balsam even more brilliantly 

 than in life. Koch describes about forty species, but some have 

 since been removed to other genera. 



EXPLANATION OF PLATE XV. 



Fig. 1.— Dorsal view of Male. Fig. 4.— Palpi of Male. 



,, 2. — Ventral view of do. ,, 5. — Dorsal view of Female. 



,, 3. — Side view of do. ,, 6. — Ventral view of do. 



