AUG 3 1900 



TWO NEW THOMISIDS — RAINBOW. 169 



TWO NEW THOMISIDS. 



By W. J. Rainbow, F.L.S., Entomologist. 



(Plate XXX.) 



The present paper contains descriptions of two new species of 

 Thomisidse, exceedingly interesting forms. The first, for which I 

 propose the name Misumena tristania, was collected by Mrs. C. T. 

 Starkey, of Neutral Bay, Sydney, at Cobbity, and presented by her 

 to the Trustees. The spider was found upon some flowers of 

 Tristania laurina, R. Br. (N.O. Myrtacefe) a tall shrub or small 

 tree, which (according to Mr. J. H. Maiden, Director of the 

 Botanical Gardens, Sydney, who kindly identified the flowers for 

 me), is found near watercourses, and is not uncommon in mountain 

 gullies. The flowers of this shrub are bright yellow, and the 

 colour is closely simulated by the spider, so that, unless it happens 

 to move, it is difiicult to detect. And, to colour must be added 

 the form of the animal itself, when studying it in connection with 

 the question of mimicry, because, when at rest, the body is posed 

 in such a manner as to add greatly to the effect. The mimetic 

 resemblance, therefore, must be regarded as protective and attractive: 

 the former, because it would assist the Arachnid in evading insecti- 

 vorous foes, and the latter, because it would be the means of 

 attracting insects upon which it feeds. 



The second species, Saccodomus formivorus, is remarkable 

 not alone, on account of its form, but also for the reason that, 

 contrary to all previously recorded facts based upon accurate 

 observations of the habits of the Thomisidse, it constructs a bag- 

 like nest. It is in consideration of this, that in founding the 

 genus diagnosed below, I propose the generic term Saccodomus. 



It has long been regarded as an axiom that all those individuals 

 and species embraced within the vast family Thomisid*, popularly 

 known as "Crab" or "Flower" Spiders, are essentially wanderers, 

 constructing neither webs nor nests for the capture of prey, but 

 relying solely upon their activity, cunning, or mimetic resemblance 

 to surrounding objects. 



Another interesting feature in connection with this species is 

 its food. Both Mr. W. W. Froggatt and Mr. George Masters, 

 in speaking to me upon the subject, said that so far as their 



