SCI/iNCE-GOSS/r. 



45 



line species, hill there lire twi) if mil iliree varieties uf 

 thFs species, which I ilescriln:. 



LiKNI TAI. I'l.ArKS OK KK.MAI.K 

 AMI MAI,K. 



Thia yenus is characterised as follows : Body 

 nearly circular. Kpimera forming one group, skin soft. 

 The genital di.scs on the inner edge of the plates, 

 three on each side, similar to those in fciilonia. 

 liyes wide apart. Swimming hairs to all legs. 

 I'alpus not chelate. Claws to all feet. 



I.thcr/ia /aiii>isif,'iiila Leliert, 1879. 



I'KMAI.K. — Body : .\ round oval. Length about 

 I '25 mm. Width about 104 mm. Colour: First 

 variety, a brownish yellow, with a T-shaped yellow 

 mark of a lighter colour, on the dorsal surface. 



Fig. 5.— /-. ttiitinst^tita. Ventral surface ok te-malb. 



Variety 2. .\11 green with a lighter tinted T-shaped 

 piece in the same position as in variety I. N'ariety 3 

 has not yet been found in Britain. It is figured by 

 Neuman as a bright red mite. The mite figured by 

 riersig is the same as our first variety. 



Lei;s. — First pair about 0'6o mm. Fourth pair 

 about I '08 mm. Colour same as body. All legs 

 have hairs, the fourth pair having the longest. .\11 

 the feet have small claws, as shown in fig. 5. 



Ki'iMKKA. — (Fig. 5.) Are arranged in one group, 

 t|uite differently from the genera Citnnpes or Lhiincsia. 

 The surface is all finely granulated, as is also the 

 chitinous parts of this mite. 



f'At.iM. — (Fig. 6.) About Q-yi mm. in length. 

 The peg is not so conspicuous in l.iiiincsia, but it has 

 a strong bristle in its place. The fourth segment is 

 also shorter and thicker than the corresponding 

 segment on many other mites. 



Ge.mtai, Area. — This part of the external 

 anatomy is very much like the genital area of Tculoiiia 

 piimaria, having the three discs on the inner edge of 



the plates. These are somclimcg covered over with a 

 small chitinous flap. 



Mai.k. — This sex is rather smaller than the rcnialc, 

 but does n<jt show sufficient diflference in structure I" 

 require a figure. 



A. tituhtsif'iiilii. 

 Ftk. ii. - Pali'is op Fi({. 8." 



KESIALK. 



-Gesitai- akha ok 

 NvMrn. 



Nymi'II. — (Fig. 7.) The nymphs are very much 

 like the adults, except in the genital arrangement, the 

 discs numbering four, instead of six, as seen in fig. 8. 

 Its length is about 0'68 mm. 



-rr^ 



Fii 



-/.. tauhisiiinitn, Ve.ntrai, surkace ok Nvmi'H. 



LofAl.lTlEs. — Not common. I found the green 

 variety in 1895 "' Bealings, SutTolk. .Mr. Scourfield 

 found the No. i variety in 1898 at Grasmere : and 

 Mr. Tavemer discovered the same coloured mite in 

 1898 at Oban. 



( To he (ontimud. ) 



MIDEOPSIS (IRBIfULARIS OF 



MULLKR. 



By C. F. Georce, M.R.C.S. 



'T'llIS very remarkable and interesting little fresh- 

 •*■ water mite was first figured and described by 

 Midler 1776-1781, under the name of Hydraihna 

 orbkularis. It was then apparently overlooked until 

 1879, when Neuman described and figured it under 

 the name of Mideopsis dcprcssa, a more descriptive 

 name than that of Midler ; for though the mite is 

 almost circular in figure, the upper surface is not at all 

 convex, but flattened and even irregularly depressed, 

 so that the edges are higher than the centre. This 

 gives the mite, when alive and moving on the surface 

 of the mud, a most singular appearance. 



1-EMAi.E. — Body : In colour M. orhiiiilnn's is 

 generally of a rather dirty yellow, with dark caeca. 

 Its appearance varies considerably with the contents 

 of the caeca. A depressed circular line runs all round. 

 very near to the outer edge. The black eyes, one on 

 either side, project beyond the edge of the body and 

 arc therefore very conspicuous. In the centre the 

 Y-shaped caecum is filled vvith opaque intensely w hile 



