YORKSHIRE ARACHNIDA IN 1912-13.* 
WM. FALCONER. 
SluithiL aitt , Huddersfield. 
Recently the very closely allied species of the Genus Pom 
homma have been revised by Dr. Jackson. t By carefully 
comparing the type specimens with those in various collections 
he has been able to clearly define the identity and character- 
istics of each species, to remove the invalid ones and add 
three others to the British list. The latter. P. thorcllii Herm., 
P. montanum Jacks., and P. pallidum Jacks., are all indigenous 
to Yorkshire, but the two last have hitherto been combined 
under another name, leaving a balance of two, which with 
six others make an addition to the county list of eight species 
for the years 1912-3, and a grand total of 317, a number 
exceeded only by Dorset. 
Mr. Winter and I have devoted a little attention to the 
mites. Most of the earthmites have in the first instance at 
least been named by Dr. George, and the beetle mites by the 
Rev. J. E. Hull, who has also supplied the list of Cleveland 
mites of the latter group, which is incorporated with others 
to form the general list which follows. 
I. — NEW TO THE COUNTY LIST. 
A. — Spiders. 
Hahnia pusilla C. L. Koch. One $, Shackleton Wood, Hebden Bridge, 
June 1913. The only other place in the British Isles where this 
spider has been found is Delamere Forest, Cheshire. 
Porrhomma thorellii Herm. — Both sexes in the cellar of a house, Slaith- 
waite, and in the open at Drop Clough, Marsden, and Shackleton 
Wood, Hebden Bridge. It is on record for Northumberland. Cum- 
berland, Durham, Somerset, and Ireland, but has hitherto been 
confounded with P. micro phthalmum Camb. 
P. pallidum Jacks. — Scarborough, Rev. R. A. Taylor ; in most of the 
woods in the Huddersfield district ; Hebden Bridge ; Hardcastle 
Crags. 
P. montanum Jacks. —In the doughs and on the moors in the Hudders- 
field district ; on the summit of Ingleborough. Both this and the 
previous species have been confounded either with P. pygmteum Bl. 
or P. oblongum Camb. 
Agyneta subtilis Camb. — Chandler’s Whin, York, 2 §s, June 1912. The 
spiders recorded under this name in Mr. Harrison’s “ Spiders of the 
Middlesbrough District,’ in Trans. Cleveland Nat. Hist. Soc were 
A. cornigera Camb. 
Thyreosthenius biovatus Camb. — Denby Dale, near Huddersfield, August 
1912. an adult male from nests of Formica rufa. This myrmecophile 
has occurred in Surrey, Sussex, Durham, and Northumberland. 
Walckencera capita Wcstr. —One 9 , beneath a stone on the summit of 
Ingleborough, June 1913. A very rare British spider which has 
occurred in Dorset, Cumberland, and Scotland. 
* For previous list see The Naturalist for February 1912, pp. 52-3. 
f Trans. Nottingham Naturalists’ Society for 1911-12, pp. 30-46. 
Naturalist 
