200 The Arachnida of Caiiil)i'i<l<i<*ltin 



ATTIDAE. Jumping spiders. 



The most familiar example is >SW///r//x .svr ///>//.<?, a zebra- 

 marked species, common on walls and fences. It I mils a 

 silken line to anchor it in case of accidents, wherever it ,L 

 and stalks insects warily till it comes within leaping distance, 

 pouncing upon them with remarkable precision. 



The rare Attus pubescem is not uncommon on the gray 

 walls of the colleges. Marpissa pomatia has already been 

 mentioned as one of the rarities of "Wicken Fen, but the allied 

 M. muscvsa is very seldom taken in Cambridge. 



Two species of Heliophanus and one of Euophrys frequent ] y 

 occur in herbage. 



Besides their habit of progressing by leaps very unequally 

 exhibited by different members of the group these spiders 

 are remarkable for their eyes, four of which are situated on 

 the forehead with their axes directed forward, two of them 

 being generally very large and noticeable. They spin no 

 web, and the great mobility between the cephalothorax and 

 abdomen, instead of facilitating their spinning operations. 

 as in the Epeiridae, is chiefly of use in enabling them to 

 direct this powerful battery of eyes with great rapidity upon 

 their prey. 



(4) Of the local Acari or mites there is, as has been said, 

 but little to record. The minute size of these creatures and the 

 lack of any satisfactory monographs, except in the case of one 

 or two groups, are serious obstacles in the way of the collector. 

 The only acarid family which has attracted any attention from 

 Cambridge naturalists is that of the OEIBATIDAE or beetle-mites, 

 and the search for them has been so recently undertaken that 

 an attempt to give anything like a complete local list is 

 decidedly premature. Perhaps a brief statement of what \\;\< 

 been done so far may serve to direct attention to a group 

 of creatures very interesting in themselves, and possessing 

 certain distinct advantages from a collector's point of view. 



In the first place the group has been ably monographed by 

 Michael in the publications of the, Kay Society, BO that the 



