296 DR. JOHNSTON ON TUE ACARIDES Of BERWICKSHIRE. 



prey. The ant was not dead ; and this was also the case in 

 the second instance.* Other two individuals had each pos- 

 session of the leg of a species of Tipula, apparently immature. 

 One of them appeared to be tapping it, as a ' nigger' would a 

 sugar-cane !" 



This is a Linnsean species, and hence an additional interest 

 in its examination. It was described, in the Fauna Suecicn, 

 in so graphic a manner that no one, with specimens before 

 him, can fail to identify it. Here is the description : — " Ha- 

 bitat in lapidibus et campis. — Descr. Magnitudo et figura A. 

 aquatici, sed corpus obscurum ; abdominis linea dorsalis longi- 

 tudinalis utrinque dilata, anterius in aliis alba, in aliis rubra ; 

 communiter anterius albida, posterius rubra ; cseterum abdo- 

 men nebulosa nigrum est, pedes rubri.'' — The mite is also 

 well characterised by Latreille, Avho makes it the type of his 

 genus Erythr^us, — " E. pedibus longissimis, articulo ultimo 

 lato, compresso ; posticis primis deinde longioribus ; corpore 

 obscure-rubro ; fascia dorsali ilavo-aurantia.'' — I cannot refer 

 to the figures either of De Geer or Hermann, quoted by La- 

 treille, but, according to Dug^s, these figures represent two 

 distinct species. Dug^s names one of them Ryncholophus 

 Degeer ; the other R. Hermann ; and he informs us that the 

 latter is very small, and has been only superficially examined 

 by him ; while the R. Degeer is larger, and as big as a flea, 

 almost globular, or rather oval, of a cinnamon-red colour, 

 brighter along the back, and garnished with black flattened 

 longish slightly curved bristles. There are four eyes in two 

 latero-anterior groups ; two stiff" bristles on the contracted 

 front of the body ; the legs in their form and proportion simi- 

 lar to still larger species, the anterior not thicker than the 

 others, but, what is a very remarkable character, the tro- 

 chanter or 2d joint is thick and globular. The legs are of 

 the same red colour as the palpi and rostrum, and are covered 

 with black flattish bristles laid to the surface. — This descrip- 

 tion inclined me at first to think that Dugc^s' Ryncholophus 

 Degeer was distinct from our Erythraeus rupestris, but the 

 slight differences may more probably be ascribed to the diffe- 



• In a subsequent letter, Mr. Hardy informs me that the mite attacks or 

 feeds on Formica fuscaalso. " It may be questioned whether it kills these in- 

 eecta or merely finds them in a disabled state." 



