104 



ARACHNOIDEA. 



CASE silken tissue like very small spiders' webs, in the midst of which 

 VIII. . , 



we can see numerous Acarids of very small size moving about. 



They are greenish yellow, transparent, a half smaller than the 



Tetranychus telarius, to which they bear some resemblance. 



We have not found this minute insect mentioned in any of the 



authors that we have consulted. Can they have confounded it 



with that which produces the ' grise ' (the red spider, T. telarius) ? 



It is extremely unlikely, because the red spider clothes the under 



side of the leaves with a close tissue which adheres very closely, 



while this species spins a very loose web like that of a spider. 



For gardeners this malady is a species of * grise.* As it only 



appears towards the end of summer, it 



^^ does not do much harm to the ripening 



^ of the grape or to the vine itself." 



No. 4. ^,\:^W/7 \':dl)\>^^/^M^ Tetranychus lintearius {Duf,, Ann. Sc. 



Nat. 1832). Acarus coccineus, Schrank and 

 Baud., Ent. Hist., p. 87? 4. Magnified sketch 

 of ditto. 



M. Dufour was the first who observed 

 this species. He lived in the suburbs of 

 St. Sever, and in the course of his rural 

 excursions, his attention was often drawn 

 to clumps of gorse ( Ulex Europceus) some 

 feet in diameter, which he found enve- 

 loped completely in a spider's web of 

 milky or opaline white, which was visible from a distance. He 

 describes it as being exactly as if a web of fine mushn had clothed 

 this thorny shrub in every direction, and penetrated by adherent 

 folds into the space between the branches. In spite of repeated 

 poring over these tufts to discover the artificers of this delicate 

 tissue, they eluded his researches for a long time. He sometimes 

 met here and there upon them various spiders, such as Epeiras, 

 Linyphiae, Uloborae, and Dolomedes ; but he was too familiar with 

 the works and the kind of life of these Araneides to allow himself 



Tetrauychus lintearius (copied from 

 Dufour 's fiijure). 



