The Scottish A'aturalist. 79 



by j^' to Y^' \ the surface is naked, or with small prickles; 

 and is wrinkled or cracked ; the colour is yellowish green. 

 The swelling is chiefly medullary, and in the heart of it live 

 several small reddish-orange Cecidomyious larvae. I h; ve 

 found it (scarce) at Dunkeld in September. 



Potentilla tormentilla Sibthorp. Of this gall I got one 

 specimen from Mr. W. Vice, which was found by him in 

 August near Loch Etive in Argyleshire. It consists of a 

 swelling just above a node, and contains three somewhat 

 rounded cells, each about T V diameter. Externally it is 

 irregularly rounded,, showing traces of the cells. Surface 

 slightly pubescent and (in the dry state) wrinkled and pur- 

 plish. Cells thin-walled, walls compact. Each cell contains 

 one white larva. 



Rosa canina L. Gall (b), Sc. Nat. vol. i. 124, formed of con- 

 duplicate leaflet, is formed by Cecidomyia rosce. Bremi. This 

 gall, as also those of Rhodites Egla?iterice and of Rh. rosce 

 and gall (c), are common throughout Aberdeenshire, and at 

 Dunkeld and Lintrathen. 



Rosa villosa L. On this species I have found galls of 

 Rhodites rosce L., of Rh. EglantericeJH..^ and of Cecido??iyia 

 rosce Bremi, and also like gall (c) of R. canina, all in 

 various parts of " Dee," at Dunkeld, and at Lintrathen. 



Pyrus aucuparia -Gasrtn. The leaves become covered with 

 blisters of various sizes projecting chiefly from the lower 

 surface. Above, they form at first small yellow spots which 

 spread, and eventually become brown and dead. In the 

 interior of each blister there is an irregular cavity almost 

 filled with interlacing hairs, among which live four-footed 

 mites (Phytopus). Common in August, near Aberdeen, 

 also sent me from Glasgow, by Mr. P. Cameron, jun. 



Crataegus oxyacantha L. About Dunkeld I observed that 

 on the hawthorn hedges the branches were frequently 

 tipped with a rounded mass of deformed sessile leaves, 

 usually covered with prickly hairs. These masses are some- 

 times as much as i^' diameter, but the colour is not 

 changed. Between the leaves live several larvae of Ceci- 

 domyia cratcegi Winnertz. Though common in Perthshire 

 I have never seen it in Forfar or in counties north of the 

 Esk. 



