1873.] REV. O. P. CAMBRIDGE ON SIBERIAN SPIDERS. 435 



The following papers were read : — 



1. On some New Species of Araneidea, chiefly from Oriental 



Siberia. By the Rev. O. P. Cambridge, M.A., C.M.Z.S. 



[Received March 15, 1873.] 



(Plates XL. & XLI.) 



In May 1872 a small collection of minute Spiders, collected by 

 Dr. Dybowski in the neighbourhood of Kuttuk on the southern 

 point of Lake Baikal in Oriental Siberia, was kindly sent me by 

 Mons. Taczanowski, of the Zoological Museum at Warsaw. This 

 collection was accompanied by two others — one made by M. Tacza- 

 nowski near Warsaw, the other by Dr. Karpinski at Kiew, in 

 Ukrania. The two last collections number between forty and fifty 

 species, chiefly of the genera Linyphia and Erigone (the latter 

 equivalent to Neriene and Walckenaera, Blackw.) ; but, although 

 some of these species are of great interest, I can detect but one 

 novelty among them {Erigone sollers, postea, p. 443, Plate XLI. 

 fig. 8) ; the rest belong to species already recorded in Northern and 

 Western Europe. 



In the Siberian collection, however, out of eighteen determinable 

 species thirteen appear to be undescribed : — one of the family 

 Agelenides, genus Lethia (Menge) ; the rest of the family Theridiides, 

 four being of the genus Linyphia and eight of the genus Erigone. 

 A point of special interest in regard to these new species is their 

 being so exceedingly closely allied to forms already described from 

 northern and western Europe, and yet so curiously and decidedly 

 distinct ; while, at the same time, the collection contained neither 

 of the species to which they are thus (severally) so nearly allied. 

 Not knowing what may have been the range or extent of the search 

 of which this Siberian collection is the result, nor the season at 

 which it was made, it is impossible to speak with certainty as to the 

 richness of the locality in respect of these minute Spiders ; but the 

 sample now under consideration leads me to believe that the part 

 of Siberia in question would yield numerous additional and still 

 more interesting forms when carefully searched. Another point of 

 interest with respect to this collection is, that the locality where it was 

 made (Baikal) is the easternmost point at which, as far as I am 

 aware, any species of Erigone has yet been found. 



Sketches of critical portions of the structure of the Spiders 

 described in the present paper have been added to the descriptions 

 (see Plate XL.) in the hope of making it easier to compare and 

 distinguish other closely allied species. 



Fam. Agelenides. 

 Genus Lethia. 

 Lethia taczanowskii, sp. n. (Plate XL. fig. 1.) 

 Adult male, length \h line. 



The cephalothorax is of ordinary form ; the lateral constrictions 



28* 



