6 PRESIDENTIAL ADDRESS. 



tain ; but as regards the discovery of new forms, so fully has the 

 work been carried out, that at the best nothing but gleanings can 

 be expected by future investigators. 



The next family, or TrombidiidcB^ contains three sections : — 

 The TetraTiychi, or Spinning Mites ; the Trombidiince, or Harvest 

 Mites ; and the BdeUince, or Snouted Mites. 



The first — which are distinguished from their congeners by 

 their semi-transparency, paler colours, and smaller size, as well as by 

 their chelate palpi — includes the " red spider " of our gardens, 

 and at times assume a serious economic aspect. Gardeners know 

 only too well the results of their ravages in hot-houses, and I have 

 seen fruit-trees completely ruined by their attacks. .The discom- 

 fort and irritation occasioned by Leptus autumnalis, another 

 member of this family, is too well known to need any description. 



The TrombidiincB have much more brilliant colouring, gene- 

 rally scarlet or some modification of red. They are found upon 

 the ground or under stones. They have raptorial palpi, and are, 

 without doubt, predaceous and carnivorous. The Bdelltnce are 

 met with in similar situations. They have much the same charac- 

 ter of colouring, and are distinguished by the mouth-parts 

 projecting like a snout, which, being usually narrowed behind the 

 palpi, gives them the appearance of having a head and neck. 

 This is further indicated by the antenni-form resemblance of the 

 palpi. The C/ieyktidce are found in company with other acarids, 

 upon which they feed, and are distinguished by their enormous, 

 rapacious palpi. They may be found in collections of chaff, old 

 hay, meal, flour, etc., and are generally distributed. They 

 number amongst themselves the somewhat unique case of a para- 

 site that is beneficial to its host — C. parastivo7'ax — living in the 

 fur of rabbits, where it feeds upon other acari, with soft bodies, 

 such as Listrophonis, etc. 



The sixth family — or Hydi'achnidcc (amongst which our friend. 

 Dr. (jeorge, has done such good work), together with the Limno- 

 charidce, or Mud-Mites — have what are called " anchoring palpi," 

 which are provided with hooks, whereby they can attach them- 

 selves to other objects. They are mostly of bright colours, and 

 are considered as T?'ombidii modified to suit the element in which 

 they live. The first have legs adapted for swimming, and are 



