52 



YORKSHIRE ARACHNIDA IN 1911. 



WM. FALCONER, 



Slaithumite, near Hiiddcrsfiehl. 



In addition to the thirteen species of spiders new to the 

 county, found in 1911, (see 'The NaturaHst,' Jan. 1912, p. 29), 

 the following notes have been made by the Committee : — 



The mountains in the West, and the neighbourhood of the 

 sea, have proved as usual during the year the most profitable 

 areas to work for additions to our list, and will probably continue 

 to be so. Great tracts in various parts of the county, in which 

 new spiders will probably occur, still await an investigator. 



Many interesting cases of abnormality, chiefly in the direction 

 of eye suppression and the malformation of defective development 

 of the palpal organs of the male, have come to hand. At Slaith- 

 waite, in May, a male of Hilaira excisa Camb. in which the eleva- 

 tion and the excisions of the caput were totally wanting, was 

 taken, but the most extraordinary instance was that of an imma- 

 ture male of Enidia hitnhercitlata Wid. (Mr. J. W. H. Harrison), 

 from the Middlesbrough district. I am indebted to Rev. J. E. 

 Hull, vicar of Ninebanks, Northumberland, for the particulars 

 concerning it. It is furnished with two additional bona-fide eyes, 

 which are the smallest of the 10, but perfectly distinct, quite 

 symmetrical in form and position, and placed between the central 

 and lateral eyes of the posterior row, but a little further back 

 on the cephalothorax. There is apparently no previous record 

 of such a reduplication of the eyes. 



On October 6th, the morning mild and sunny, with a gentle 

 breeze from the south-west, an interesting series of aerial flights, 

 a method by which many spiders are able to disseminate themselves, 

 was witnessed. The threads of the flying spiders became en- 

 tangled in some elevated iron railings fixed in a large asphalted 

 enclosure, 48 yds. by 28 yds., whereby the progress of the little 

 aeronauts was arrested. The great bulk consisted of adults of 

 both sexes of Erigone promiscua Camb., with several Erigone atra 

 Bl., and Dicymhiwn nigrum Bl., a pair of Savignia frontata BI., 

 a male Bolyphantes kiteolus BL, two immature Leptyphantes, a 

 pair of Centromeria concinna Thor., and one male C. hicolor Bl. 

 This occurred at Slaithwaite. 



In the following list of rare Yorkshire species, none is in- 

 cluded which has already received notice in any of the reports of 

 the various meetings held during the year {Vide " Naturalist," 

 June, pp. 233-5, 3-nd October, pp. 363-4), or in Mr. Winter's 

 " Additions for the Airedale and Wharf edale Area," infra. 



Dysdera crocota C. L. Koch. Middlesbrough. $. J. W. Harrison. 

 Prosthesinia petiverii Scop. Skipwith Common. One immature §. Second 

 Yorkshire example. New to E. Riding. 



Naturalist, 



