102 ARACHNOIDEA, 



CASE of their leaves. M. Boisduval calls it Acarus tini, but we see 

 nothing in his description to distinguish it from telarius. 



M. Boisduval, in his " Entomologie Horticole," also mentions, 

 without much description, a number of other Acari, which he 

 thinks have probably been erroneously confounded with telarius, 

 but which from their different forms and habitat he regards as 

 distinct. The above, in our opinion, do not differ from that 

 species. Others we have allotted elsewhere. As to the following 

 we are in doubt, although it seems not improbable that they too, 

 or at least some of them, may be merely varieties of T. telarius. 



Tetranychus cucumeris [Boisd.), Ent. Hort., p. 84. 



This mite lives on the cucumber and the gherkin ; it is more 

 globular than telarius, a little smaller, of a uniform shade. In some 

 years it is common enough in the kitchen garden. When the Cucur- 

 bitacese are attacked by the grise, the best plan is to take out the 

 sick plants. We must not confound the grise with a species of Myce- 

 lium, a kind of Erysiphe, which forms milky white spots on the leaves. 



Tetranychus rosarum {Boisd.), Ent. Hort., p. 84. 



This, according to Boisduval, is more elongated than the pre- 

 ceding ones, and is of a very pale green colour, almost trans- 

 parent ; it lives under the leaves of certain varieties of rose trees, 

 and is found sometimes alone, and sometimes together with 

 another httle red mite which he designates under the name of 

 Acarus pucciniae. 



He says that he never met with these two Acarids but on 

 diseased leaves, of which the lower surface was covered by the 

 Uredo ros^ and the Puccinia rosse growing pell mell one beside 

 the other. They seemed to be living at the expense of these two 

 hypophyllous fungi. The rose leaves invaded by these two vege- 

 table parasites are underneath of a yellow-ochre colour besprinkled 

 with large brown dots ; on the upper side variegated with spots 

 and marblings of different colours, in which we may sometimes 

 see the little larvae of a tenthredo eating the parenchyma. 



