Insects, etc., Injurious to the Plum. 



401 



BEETLE MITES. 



(Oribatidce.} 



These mites (Fig. 269) take their popular name from their hard 

 shiny nature. Some are black, others red or brick-dust red. 



One species, Oribata lapidaria, is very frequent on fruit trees, 

 especially plums and damsons. 



They are frequently thought to be injurious, but no proper 

 evidence lias yet however been brought forward to prove this, and in 

 all cases investigated by the writer they were found not only not to 

 be injurious, but to be actively beneficial, for they feed on lichens 

 and fungus spores. They have been watched feeding upon the fruit 

 organs of the canker fungus (Nectria ditissima). 



FIG. 269. BEETLE MITES OR Oribatidx. 

 A, adult Oribata lapidaria ; B, nymph ; C, stigmatlc organ ; 



Ai and Bi, claws. 

 (From ' A Text Book of Agricultural Zoology.' Theobald.} 



They cluster together in dense masses, hiding under moss, bark, 

 sacking, etc., and appear to hibernate in the adult condition. 



The species I have taken to be(l) Oribata orbicularis, Koch, is 

 apparently the species named here, so I am informed by Mr. Cecil 

 Warburton. 



The mites recorded by me from chestnuts and fruit in Sussex 

 were referred to Albert Michael and he identified them as 0. 

 orbicularis (2), so that we appear to have at least two species on 

 fruit. 



In 1904 they were very abundant in parts of Kent. 



Mr. Howard Chapman wrote that at Dartford he found " more 

 on plums than on pears and apples. On plums (Victorias and 

 Orleans), after taking the grease bands off, there are noticed quite a 



2 D 



