204 The Scottish Naturalist. 



England {e.g.^ at Kew, where I have seen them in great 

 abundance), and on the Continent, so we may expect them 

 to occur in other locaHties in Scotland. They are of great 

 historical interest, as being among the earliest described 

 mite -galls. Reaumur describes and figures them in his 

 ' Me'moires pour servir a I'histoire des Insectes' (1737), and 

 tried to discover the maker with the aid of a lens. Turpin, 

 in 1833, ascertained that they were the work of a mite, 

 which he called Sajroptes gallariLin Tilice ; and not long after 

 Duges traced the development of the galls. They have 

 since been noticed by almost all French and German writers 

 on galls, and the galls themselves received the name of Cera- 

 tojieon extensjwi from Bremi. 



Galium verum L. — {e) Leaf-rolling by a species of gall-mite. It 

 resembles the deformities produced on Galium aparine ( {b) 

 vol. IV., p. 15), and on G. saxatile ((a) 1. c, p. 15); the 

 leaves of the upper whorls have the margins revolute so as 

 to form two tubes, while the leaves become slightly thick- 

 ened and distorted, and assume a yellowish tinge. The 

 mites live in the interior of the tubes, usually only a few in 

 each. Not uncommon near Old Aberdeen, but readily 

 overlooked, as they are very inconspicuous. In the ' Zeits- 

 chrift fiir die gesammten Naturwissenschaften,' vol. xxxiii. 

 pp. 344-47, and vol. xlix. pp. 361-62, Dr Thomas of Ohrd- 

 ruf has described these deformities as occurring on the 

 species of Galijuu mentioned above, and also on G. sylvcstre 

 and on G. inollugo, so that we may expect them to occur on 

 these plants also in Scotland. 



Betula alba L. — (/) Scattered over the blade of the leaf, pro- 

 jecting on both surfaces as conico-cylindrical warts V35 — V25 

 inch in diameter ; surface naked, smooth, and green or red at 

 first, becoming wrinkled and brown afterwards ; walls thin in 

 proportion but woody, opening below by a narrow passage 

 filled witli hairs. In the interior live numerous gall-mites 

 {Phytoptus, ,006- .007 X .0012 inch). These galls are most 

 readily detected by the shotty feeling when the leaf is 

 pressed between the finger and thumb. As many as 50 may 

 occur on a single leaf. At Banchory-Ternan, ist September. 

 'I'hey are well described by Dr Thomas in the ' Nova acta 

 (ler Ksl. Leop.-Carol. Deutschen Akademie der Naturfor- 

 scher,' vol. xxxviii. pp. 266-68, figs. 12-15. 



