Palaeozoic Arachnida of North America. 71 



ORDER KUSTARACHxNAE 



Head completely fused with thorax. Abdomen segmented, pro- 

 bably with a pedicel. All coxae radiating from a central, small 

 sternum, probably immovable. Coxae of pedipalpi fused together 

 without a suture. Pedipalpi chelate. Chelicera not known. Legs 

 thin and long. Eyes to the number of two, placed on a tubercle. 



The above characters make it impossible to place the three species of 

 the only genus of this order under any other order. Pocock has pointed 

 out that Kustarachne sulcata Melander is a Curculioides and tliinks 

 that the other species may also belong to the order Ricinulei. As will 

 be shown further below, Kustarachne sulcata is a Curculioides, but 

 K. tenuipes Scudder, K. extincta Melander and K. conica n. sp. have 

 nothing in common with either extinct or recent Ricinulei, while they 

 are very closely realated to each other. 



Genus Kustarachne Scudder 1890. 



With the characters of the order. Genotype K. tenuipes Scudder. 

 Key to the Species of Kustarachne. 



1. Abdomen with 10 sternites K. extincta 



+ abdomen with 7 sternites 2 



2. Abdomen conical without pygidium 



K. conica 

 + abdomen oval with a pygidinm 



K. tenuipes. 



Kustarachne tenuipes Scudder. 

 Plate VI, figs. 33, 34; text figs. 34, 35. 



K. tenuipes Scudder, Mem. Boston Soc. Nat. Hist., Vol. IV, 1890, 

 p. 450, pi. 40, fig. 7. 



The type and only specimen of this species, originally labelled No. 

 1756 a and b is now in the collection of the U. S. National Museum 

 as No. 37967. Since Scudder 's description is incorrect owing to the 

 specimen not having been properly cleaned, the following description 

 should take its place. 



Total length 11. 5 mm. Cephalothorax with strongly recurved 

 posterior edge, rounded in front, quite flat, 3.0 mm. long in the median 

 line, 5.8 mm. wide between the posterior corners. About ^/g the 

 length of the cephalothorax from its anterior edge is the mould of the 

 transversely ellipsoidal eye tubercle with two perfectly round eyes. 

 Chelicera missing. The coxae are all triangular, apparently immo- 

 vable, radiating from a small sternum. The coxae of the pedipalp 

 are completely fused together without a sign of a suture. The palpi 

 themselves are composed of only four segments, the last two forming 



