The Scottish Naturalist. 109 



ently belonging to a Cecidomyia. After a time the galls wither, and 

 turn dry and brown ; and in this state they much resemble the spots 

 caused by certain species of Fungi (Septoria, &c), a resemblance in- 

 creased by the fungi that grow on the surface of the gall after the escape 

 of thelarv;e. The latter leave the galls when full-fed ; and apparently 

 become pupae in the soil, (c) Mite-galls of the inflorescences, well- 

 known in Germany under the name " Klunkern;" first described bv 

 Vallot (Mem de l'Acad. de Dijon, 1839, p. xxxiv), they have been rede- 

 scribed by Drs. Thomas, F. Loew, Schlechtendal,and others ; and are 

 excellently figured by Dr. F. Loew(V. Z. B. Ges. Wien, 1878, t. II, f. 2). 

 They are apparently rare in Scotland ; and, though I have found 

 shrivelled and broken examples in Aberdeenshire, I have not found 

 them in the fresh state. 



In the early summer of 1886, Dr. Buchanan White kindly sent me 

 two or three examples found by himself in the neighbourhood of Perth. 

 The mites (a species of Phytoptus), were not to be discovered on 

 these examples ; but the galls so entirely agreed with Dr. Loew's 

 description of the galls as to prove that their production is due to the 

 same agency. They form very irregularly rounded growths, from the 

 size of a pea to that of a walnut, at first brownish-green, afterwards dark 

 brown. The peduncle of the inflorescence is a good deal distorted, 

 and the flower-buds cease to be recognisable as such, and form mere 

 projections on the surface of the mass. The surface is closely covered 

 with very short erect hairs ; but these tend to fall off. On section 

 the galls prove to be solid ; and soon become extremely hard, with no 

 cavities in their centre. They are chiefly composed of modified cel- 

 lular tissue. Dr. Loew found large numbers of a very small, trans- 

 parent Phytoptus in the fresh galls ; the easiest method of obtaining 

 them is to wash the galls in water, and to examine the sediment from 

 the washings with the microscope. 



Quercus Robur L. (aa.) Galls of Aphilothrix corticis Htg. have 

 already been recorded by Mr. Cameron from the vicinity of Glasgow ; 

 but last year I observed them for the first time near Aberdeen, in two 

 or three places. They are sunk in groups in the bark of roots or of 

 stems, especially in the thickened mass (callus) surrounding wounds. 

 They are not visible while young, in which state the outer layer of -the 

 wall is continuous with the cortex; while the inner layer is harder than, 

 but united with, the outer. The galls are oval, with their long dia- 

 meter vertical to the surface. When dry the top falls off, showing the 

 cavity, and the galls become conspicuous. They are formed in 

 autumn, but are most noticeable in spring, {bb.) The spring form of 

 gall of the above insect occurred on the same trees as the bark-galls 

 just described. The generation that forms the spring galls is known 

 by the name of A. gemmatus Adler. The gall formed by it grows in 

 the young buds ; it is sessile, oval, only about 1 or 2 mm. long, but 



