io6 ARACHNOIDEA. 



CASE was not able, owing to the diminutive size of these Acarides, to 

 estabhsh the fact of their existence by direct observation. He 

 could not ascertain what they fed on ; but their great numbers 

 indicate that they, like their congeners, are herbivorous. Animals 

 that are social are very rarely predaceous. 



M. Lucas mentions (Ann. Soc. Ent. Fr., 1869) that it is much 

 rarer in Normandy than^ in Brittany, whence it may be doubted 

 whether it is likely to be met with in this country. Being desirous 

 of carrying off a souvenir of this able weaver, he cut some 

 branches of gorse on which a few milHons of this species had 

 established themselves, and, putting them in a box, the mites set 

 themselves to spin a web of milky white, which he exhibited to 

 the Entomological Society of P>ance, and he draws attention to 

 its thickness and its extreme delicacy and fineness, and its quality 

 of not adhering to the touch, justifying entirely M. Leon Dufour's 

 comparison of it to a piece of the finest muslin. 



In the environs of Marseilles, where the camellia is cultivated 

 on a great scale, the underside of the leaves is often observed to 

 be disfigured by white spots or blotches. M. Laboulbene (Ann. 

 Soc. Ent. Fr., 1865) ascertained that these were caused by Tetra- 

 nychus lintearius. The largest individuals are scarcely the third 

 of a line in length, obtuse, oval in shape, of a vermilion red, more 

 or less intense, and with the legs pale, one or two obscure patches 

 on the back at the sides, two or four ranges of long white hairs 

 run down the back. In the fresh individual, in which the body 

 is plump and the skin well stretched, no trace of a division 

 between abdomen and thorax is visible, but when somewhat 

 shrunk a slight constrictive division becomes visible. M. Dufour 

 gives a figure of this species, which we have copied, although we 

 do not think it has the look of being a good portrait. 



M. Boisduval observed it under the leaves of the syringa or 

 sweet pipe. It is possibly, too, the same species that is noticed 

 by him under Schrank's name of Acarus coccineus. He says that 

 it makes a tapestry of fine silk, very light, to which the dust sticks, 



