315 



GENUS OXYPTILA, Sim. TnOMISUS, Blachw., in part, 

 and XYSTICUS, Cambr., in part. 



The gonus Oxyptila has been founded by M. Simon for the 

 reception of a number of small Thomisides, hitherto usually 

 included in tho foregoing genus (Xysticus), but which have always 

 formed a very compact group within it. 



Tho distinctions on which tho separation of these species from 

 Xysticus has been made did not at one time appear to me 

 sufficiently strong to warrant the formation of a new genus ; on 

 a further and more extended examination howevor of all tho 

 species known to mo, I think that Oxyptila is both a tenable, and 

 a very useful genus, reducing the numbers of the, still large* 

 group Xysticus, and rendering its generic limits more precise. 



The main differences between Oxyptila and Xysticus appeal- to 

 be first the narrower fore part of the caput, the lateral margins 

 of which are more compressed ; secondly, the position of the eyes — 

 tho posterior row being more strongly curved, and its two 

 central eyes nearer together than each is to the lateral eye next 

 to it, while in Xysticus the two centrals are either further apart 

 than from the laterals, or elso tho four are equidistant from each 

 other. Tho four central eyes, also, instead of forming a square, or 

 a quadrangle broader than long as in Xysticus, form in Oxyptila 

 a quadrangle longer than broad. The abdomen of the male 

 appears to be always more nearly of the size and form of that 

 of the female ; and the dentated band along the middlo, so 

 conspicuous in most, and traceablo more or less in all true 

 Xystici, is never discernible so far as I am aware (excepting 

 occasionally in the female of Xysticus horticola, 0. L. Koch., 

 Thomisus versutus,B\ . ) in Oxyptila, which has however a characteristic 

 abdominal pattern of its own, consisting of an elongate central 

 marking running backwards from the middle of the fore margin, 

 of a fusiform shape, often indicated only by a dark marginal hue, 

 sometimes perfect, but frequently broken and interrupted ; this 

 fusiform marking is followed by several, more or less perfect, 

 transverse, dark or light-coloured bars or stripes, often by both. 



