hy some Insects wpon Plants. 187 



6. C. Helianthemi ; ochracea, minuta ; oculis brunneis ; thorace sub- 

 flavo, atomis strigisque fuscis variegato ; scutello cameo ; facie, 

 pedibus, antennisque flavis, his 14-articulatis, articulis, Imo ct 

 2ndo brevibus, ultimo subelongato, ceteris angustiore, reliquis pe- 

 dicellato-subcylindricis, capitulis subcylindricis versus bases sub- 

 coarctatis, pilis longis biverticillatis obsitis ; alis mediocribus, sub- 

 albido-flavidis, pallide uervosis, subcinereo-maculato-fasciatis, exi- 

 tibus fasciarum maculas 7 cinereas marginales efficientibus, angulo 

 nervi furcati subacute ; halteribus albis, capitulo modico. Long, 

 corp. lin. ^ ; alar. exp. lin. \\. ^ . 



Obs. Habitu C. bicoloris, sed abunde differt ; a C.punctijjenni, Meig., 

 numero articulorum anteiuiarum minore, facile dignoscitur. 



3. Spotting of the leaves of Grasses, (Sfc. 



I have often been unable to account for the suddenness with 

 which the leaves of Ranunculus repens, and of many grasses [Tri- 

 ticum repens and Alopecurus jjratensis being of the number) 

 growing by the sides of walls, become whitened in minute specks 

 and irregular lines all over the upper surface, as if the colour had 

 been extracted from them, or had left some cells by a kind of 

 elective preference for others. I have recently found this to be 

 occasioned by a small dusky red-legged mite, which harbours 

 under stones, but comes out in the sunshine in immense swarms 

 to feast upon the foliage. Owing to the numei'ous mouths at 

 work, large patches, especially in the grasses, are speedily drained 

 of their sap and become quite dead or blighted. The mite is not 

 described in any accessible work on the Arachnides. Dr. John- 

 ston considers it to be a Rhyncholophus, but that the structure 

 of the fore-legs indicates an affinity with Bryohia. From Trom- 

 bidium it differs, he observes, in the eyes being sessile and on the 

 shoulders. I have named it R. haustor, and the following spe- 

 cific character may serve to distinguish it : — 



R. subovatus, atro-sanguineus, fronte, vitta dorsali, marginibus ele- 

 vatis corporis plerumque, pedibusque coccineis ; oculis, serieque 

 marginali grauulorum rufis ; pedibus anticis gracilibus extensis 

 posterioribus duplo longioribus. Long. corp. vix lin. i. 



It occurs likewise upon the leaves of fruit-trees, but the dusky 

 parts are then greener. In autumn it is much darker and more 

 convex. It runs rapidly, agitates its fore-legs like antennae, 

 sloughs off its skin where it feeds, and leaves behind it an excre- 

 mentitious deposit that glitters like honey-dew. 



4. Adelges Abietis. 



This insect forms the cone-like excrescences on the spruce-fir. 

 The original matriarch lives outside the gall, remaining all winter 

 in a dormant state at the root of the bud. As soon as the bud 



13* 



