60 



ON THE ENGLISH SPECIES OF RED SPIDER. 



? Tetranychus yothersi McGregor, Ann. Soc. Ent. Amer. 1914, 

 vii. pp. 355-357, pi. xliii. figs. 1- 8. 



S . Penis very like that of 0. simplex Banks (from date-palms), 

 being small and curved at the end. 



Palj^. Terminal finger absent or very minute and inconspicuous. 

 Dorsal sensory finger short and \QYy slender. 



2 . Pal]). Terminal finger not nearly so wide as in 0. ulmi, 

 being short but only of moderate width ; sometimes it is slightly 

 clavate. Dorsal sensory finger quite short and slender. 



Colour whitish or pale brownish with black markings. 



^ggs variable in colour, being either whitish, pale yellow, or 

 reddish. 



Measurements, d , length 220 /x ; $ , 270-310 yu. 

 Host plants. Oak-trees. 



Note. — Targioni Tozzetti seems to have been the first to observe 

 Tetranychus occurring on oak-trees, but he does not give the 

 species a name. 



In his ' Acari dannosi alle piante coltivate ' Berlese copies 

 Tozzetti's brief descriptions, and gives the name quey^cinus to this 

 mite, and mentions also the Tetranico verde del leccio " [T. vires- 

 cens), which is probably the same species. Oligonychus hrevipodus. 

 also from the evergreen-oak, seems to be another synonym of this 

 species. Both Canestrini and Berlese in later publications 

 rega.i'ds this species as a synonym of Tetranychus ielarius. The 

 specimens found on oa*]<:s in this country (at Wimbledon Common 

 and Kew) belong, however, to the very distinct species of Parete- 

 tranychus ( = Oligonychus) described above, which is easily recog- 

 nised by the structure of the palp. 



I take the opportunity' to include the diagnosis of a species of 

 Oligonychus from date-palms in Mesopotamia : — 



4. Oligonychus simplex Banks?, 1914. 



? Tetranychus simplex Banks, J. Ent. Zool. Claremont. Cal. 

 1914, vi. p. 57. 



(S . Penis. Chitinsed part of penis very short, and it terminates 

 as a very minute curved hook. 



Palp. Terminal finger very like that present in 0. ulmi, being 

 rather short, but it is slightly blunter. Dorsal sensory finger 

 spindle-shaped, being rather short and slender. Spine on upper 

 surface of palp borne 9n a distinct angular piojection. 



$ . Palp. Terminal finger more slender than in 0. ulmi, but 

 still it is fairly stout. Dorsal sensory finger fairly long. 



Measurements. 6 , length 275-290 />t ; $ , 280-385 /x. 



Host plant. Date-palm, Basra., Mesopotamia ; numerous speci- 

 mens collected by Capt. P. A. Buxton. 



