ON SOME RARE ARACHNIDS 419 



oi Prosthesinia latitans (L. Koch) since there are no figures of 

 it in British literature. The spider has, however, occurred in 

 Britain before. Another observation is that on the web- 

 spinning habits of Theridiosoma argenteolum (Camb.). The 

 beautiful Epeiroid web of this little spider had not previously 

 been observed in Britain, and it is not yet certain that our 

 species is identical with either the European or American 

 members of the genus. There are several other records of 

 rare or semi-rare species, and I here include also the figures of 

 the new Tartarid Tritliyreus Bagnallii (Jackson) described in 

 a previous paper. 



Let me again thank my correspondents for all their kindness 

 in sending me specimens. To Messrs. AVallis Kew, Evans, 

 Hull, Falconer, Butterfield, Britten, Pack-Beresford, and W. P. 

 Winter my thanks are due. Once more too I must record my 

 thanks to those authorities who have so kindly assisted me 

 with advice and specimens. These are, of course, Mr. Cam- 

 bridge, who has seen all the new spiders and many of the 

 others, and has given me much assistance and information 

 both by letter and during a stay at Bloxworth Rectory in June. 

 M. E. Simon has also examined the little Oonopid and con- 

 firmed my identification of it, while Professor Kulczynski has 

 compared several of my specimens with Continental forms in 

 his possession. 



Oeder ARA:N^EJi: 



Family OONOPID^ 

 Triaeris stenaspis (Sim.) (Plate X., figs. 12, 12a, 12b.) 



This little spider bears a strong superficial resemblance to 

 Ischnothyreus velox (Jackson). It can, however, easily be 

 distinguished from that spider by the arrangement of its eyes, 

 by the structure of its legs, and by striking differences in its 

 scuta. 



The male is unknown. The female is i'8 mm. in length, 

 which is about the average of /. velox. In general facies it 



