328 The Scottish Naturalist. 



Polygonum viviparum, P. amphibium, var. terrestre, 



P. Persicaria, all have the margins of the leaves 

 rolled back, and fleshy, and reddish-brown, yellow, or 

 bright-red, and very conspicuous. The margins may be 

 altered for only a small part of their length ; or, if several 

 galls are more or less united, the galls may extend from 

 base to tip of the leaf. These galls are the work of Oeci- 

 domyia Persicarice L. They are local, but often abundant 

 where they occur. Dr. Buchanan White gave me speci- 

 mens on P. viviparum from Braemar (T.S.N., II., 253, 

 T.A., I., 67, 68), and on P. Persicarice from Dunkeld, 

 (T.S.N., II., 253). I have them on P. amphibium var. 

 terrestre from near Aberdeen, from Arbroath, from Dun- 

 keld, and from Perth (T.S.N., II., 253). On P. Persi- 

 carice Mr. Hardy records them (Scot. Nat., III., 315), 

 from E. Lothian, and Mr. Binnie (B. I., 162), from 

 Glasgow. 



Ruiliex Acetosella (Sheep's Sorrel) has the flower-buds very 

 often galled, in the vicinity of Aberdeen, by C. Rumicis 

 H. Lw.; but, being very inconspicuous, the galls are very 

 readily overlooked. The buds become swollen, but do 

 not open, and the sexual organs abort. Usually many 

 flowers are attacked on each plant. The midges are 

 very easily reared from them. (T.S.N. , New Ser., I., 

 216.) 



Urtica dioica (Common Nettle) bears galls of C. XJrtiece Ferris 

 abundartly, from Orkney southwards, in summer and 

 autumn. The galls grow on the stems or on the leaves 

 at the tips of the stems, usually one on each side of the 

 base of the midrib, or on the leaf-stalks, or on the flower- 

 stalks ; and sometimes there is a mass of them united in 

 the terminal bud. They are irregularly globular, each 

 being about 6 mm. (J inch) diameter, brownish-green 

 above, paler below, hairy, with a fleshy wall enclosing a 

 cavity inhabited by several white larvae. (T.S.N., I., 159;. 

 ' T.A., L, 68; B.I., 162.) 



(To be continued.) 



