146 ON NEW AND RARE BRITISH ARACHNIbA. 



marginal row of black bristles on the upper side, and an 

 obtuse prominence behind. The digital joint is large, obtuse in 

 front, where it appears to be of a somewhat bent form. The 

 palpal organs are large and complex ; their form was rather 

 obscured owing to their being thrust out of place by the 

 inflation of a membranous lobe connected with them ; but the 

 distinctiveness of their structure may be seen from the figures 

 given. 



Maxilla, labium, and sternum dull yellowish. 



Abdomen oviform, pale dull whitish yellow. 



The female resembles the male in colour and other general 

 characters, and the form of the genital aperture is very dis- 

 tinctive. 



Both sexes were received from Mr. H. Donisthorpe, by whom 

 they were found in the nest of the ant, Lasius fultginosus, at 

 Wellington College in the spring of 1906. 



TmetiCUS emptUS, Jackson. PL A., Figs. 26-31. 



Centromerus emptus, A. R. Jackson. Proc. Chester Soc., 

 Part vi., No. i, May, 1907, p. 4, PI. i, Fig. 16-22. 



Adult male, length i-i6th of an inch ; adult female, ditto. 



Cephalo thorax, legs and other foreparts pale yellow, slightly 

 suffused with dull sooty brown. The lateral marginal impres- 

 sions at the caput are almost or quite obsolete. 



Eyes rather small, closely grouped together, on black spots, 

 hinder row curved, convexity of curve directed backwards, and 

 its eyes separated by almost equal intervals of less than a half 

 diameter ; front row straight, its central pair very small and the 

 eyes not quite contiguous, but separated by half a diameter from 

 the laterals, which are largest of the eight. Those of each 

 lateral pair are seated on a strongish tubercular prominence ; 

 height of the clypeus equal to half that of the facial space. 



Legs, moderately long, slender, 4, i, 2, 3, dull yellowish, the 

 tibiae of the first and second pairs slightly suffused with dull 

 sooty brown. 



