46 
so frequently produced on leaves by fungi; indeed it was while 
examining the spots in search of fungi that I detected their true 
cause. The young gall is lenticular in form, projecting very 
slightly from both surfaces of the leaf, slightly more so below, 
where the orifice is situated. The gall is usually from ‘5 to 2°5 mm. 
across, and is about twice as thick as the leaf around it; but its 
surface hardly differs from that of the leaf in colour, though it is 
at times yellowish-green. However, in course of time the colour 
changes through yellow to brown as the tissue dies. On 
microscopic examination the palissade cells are seen to be hardly 
altered, but the cells of the tissue below them become much 
enlarged, and leave large interspaces among them; and in the 
interspaces the mites live. Before the fall of the leaves the mites 
may be found crawling over them, having abandoned the galls 
through the opening below. Frequently a leaf bears many galls ; 
and on some trees hardly a leaf can be seen free from them. I 
have found them abundantly in Aberdeenshire, Forfarshire, and 
Perthshire, and have no doubt that they will be found almost 
wherever looked for. 
ULMUS CAMPESTRIS L. :— 
Galls ot Phytoptus, doubtless the same species as makes the 
galls just described on U. montana, are common in the same 
localities as the latter, and are exactly similar in all respects. 
They have been described from this tree from Gotha, Wurzburg, 
and the Tyrol by Dr. Thomas, and from Weidling in Austria by 
Dr. Fr. Loew. 
JUGLANS REGIA L. :— 
Erineum Juglandinum Pers. was sent me in the month of June 
by Dr.Buchanan White from Perthshire, where he had gathered it. 
It is made by a species of Phytoptus, like the other Zrinea. 
Greville described it under the name £. subulatum in his JAono- 
graph of the genus (f. 75, 4/2, f 4), and under the name 
E. Juglandis D.C. inhis “ Mora Edin.” (p. 450), and in his 
“Scot, Crypt. Flora” (V., t. 263, 7-2), recording its occurrence 
near Edinburgh. The gallis situated on the lower surface of the 
leaves, and consists of a patch of yellowish-gray hairs, very closely 
packed together ; the outlines of the patch are bounded by nerves 
of the leaf, and it is thus often quadrangular in form, and may be 
as much as 20 mm. in its long diameter. The hairs are slender, 
simple, and pale, seldom showing any marked irregularity in form. 
The patches generally lie in depressions of the lower surface, to 
