io8 



ARACHNOIDEA. 



No. 



K=^ 



CASE that the stems and branches of such trees seemed covered with 



VIIi 



a bright glaze. Can this be a fine web ? It is similar to the red 

 spider in form, but a trifle smaller, more elliptical, slightly broader 

 in front, and pale whitish ■'^ellow instead of reddish. Like it, it 



is semi-opaque and velvety, the con- 

 tained food being at times visible 

 through the skin. The figure here 

 given is a magnified representation 

 of it. It covers the under side of 

 the leaves with a slight web of silk, 

 which gives it a brilliant surface. 

 On this the mites move about with 

 a good deal of quickness. They 

 do not gnaw or eat away the leaves. 

 Like their fellows, they merely suck 

 the juice of the leaf; but although 

 almost microscopic in size they make up for their minuteness by 

 their numbers, and under their attacks the leaves rapidly shrivel 

 up and die. They chiefly congregate on the under side of the leaf, 

 those found on the upper side being mere wanderers, while on the 

 under side they are sometimes crowded together in vast numbers ; 

 for example, we have seen them so thick on the leaves that they 

 looked as if they were not merely sprinkled with a yellow orange- 

 coloured powder, but as if it was actually in parts heaped up on 

 them, so that none of the green colour of the leaf was visible. 

 Their appearance in such excessive numbers is said to follow 

 certain peculiar states of the atmosphere. 



Tetranychus tiliarum. The Lime Tree mite. 



Tetranychus socius. Copied 

 trom Hermann. 



Tetranychus socius {Herm.\ Acarus sociarius, 

 Mull.—V^. Enlarged figure of ditto. 



This species also is regarded as a sy- 

 nonym of T. telarius by Claparede, as to 

 which we give no opinion. It was first 

 described by Hermann, and the most pro- 

 minent character given was that the palpi 



