100 



24 • 



16 



50—144. 



lOO 



24 : 



16 



60—150, 



lOO 



: 9 



8 



32 — Circa 144. 



ICO 



14 



14 



18—120.] 



TERHESTRIAL ACARI OF THE TYNE PROVINCE 39 



X. vulgaris (Canestrini) 



2. vulgaris {mi hi) 



3. dccipiens, Thorell 



[lignicola, Can. 



The first two agree in having the length of the 

 rostrum double its width at the base ; but there 

 is discrepancy in the body-lengths which are : 

 ( I ) '66 mm. ; (2) 'SS mm. : [ (3) 1*50 mm]. Again, 

 according to Thorell, decipiens has the sixth 

 article of the fourth leg nearly twice as long as the 

 fifth : in the other two these joints are about equal. 

 The rostrum of decipiens is four times as long as 

 wide at the base, which is approximately the pro- 

 portion in lignicola, Can. 



From these facts I conclude that decipiens, Thor. is a 

 valid species allied to lignicola, Can., and certainly 

 not a variety of vulgaris as Triigardh supposes. 

 Moreover my littoral z7//^rt;m presents no character 

 sufficient to separate it from vulgaris. Can., but in 

 view of the discrepancies already noted together 

 with the spiny nature of the dorsal setae it may be 

 very well be named var. maritima. 



75. Bdella decipiens, Thor. 



Ireland (Halbert). Whether this is genuine decipiens 

 or my vulgaris var. maritima, I do not know. 



76. Bdella lignicola. Can. 600 /x. 66,67,68. 



Crimson pink; often more or less purplei The 

 smallest species of the genus. 



77. Bdella calva, Hull, 67. 



Very pale pink. The mandibles long and very 



slender. 

 West Allendale, under a rotten log. 



78. Bdella silvatlca, Kriimer {fide Thor,) 67. 



West Allendale, under stones and in moss ; not 

 common. 



