256 The Scottish Naturalist. 



The galls appear as yellowish spots, which become brown, 

 and at last dark-brown, and are irregularly raised and corrugated 

 on the surfaces above and below. On section, the cells of the 

 internal tissues of the leaf are found to be irregularly torn apart, 

 leaving large interspaces in which the mites live in considerable 

 numbers. A small opening on the lower surface of the leaf 

 shows the point of entrance, and allows exit to the occupants. 

 These galls vary much in size, having no definite limits, and 

 often unite together so as to cover almost the whole surface of 

 a leaf. 



Sedum rhodiola, Dc. — Galls of mites (Phytofttus), described 

 by Dr Fr. Loew in ' Verhandl. d. Z. B. Gesellsch.,' Wien, 1881 

 (vol. xxx. p. 7, t 3., f. 4). 



The galls may be restricted to defined spots on any part of 

 the leaves, though more commonly near the base, or they may 

 spread over the whole of the young leaves towards the tip of a 

 branch ; and Dr Loew states that they often affect the flowers 

 also. The form of the isolated galls is usually rounded or oval 

 (but the outline may be irregular), and in size they usually 

 reach ^ to ^ inch across. Each consists of a prominent ring 

 of tissue, irregularly fissured and warty on the free edge, which 

 bends inwards so as to leave only a narrow fissure or opening 

 in the middle. In colour they are yellowish green, passing into 

 purple. The surface bears no hairs. On section, the ring is 

 found to surround a space into which project small fleshy cel- 

 lar outgrowths from the surface of the leaf, and between these 

 the mites may be found. 



Tanacetum vulgare, L. — The edges of the leaf-segments 

 are rolled in by mites {Phytoptus), either in limited spots, or, in 

 the younger leaves near the tip of the shoot, in their whole 

 length. The affected leaves become covered with a hoary coat 

 of white silky hairs, thereby becoming somewhat conspicuous. 

 The mites live in the tubes formed by the leaf-margins in 

 considerable numbers. These galls seem the same as those 

 described by Dr Thomas (Giebel's ' Zeitschrift,' 1877, p. 365), 

 from Boppard on the Rhine. 



Fagus sylvatica, L. — In this magazine (vol. i. p. 235) I 

 described galls on leaves of beech, which I referred to Cec. 

 ( Hormomyid) piligera, H. Lw., though they did not possess the 

 erect hairs said to occur on the typically developed galls of 

 that insect. I have since then found galls of C. (//.) piligera at 

 Forres, and at Glamis in autumn of 1880, as well as in numer- 



