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separate from one another ; they occur seldom on the petiole. The 
gall projects on both surfaces as a conico-cylindrical wart 3';-2's 
inch diameter, with a naked surface, at first green, or red and 
smooth, afterwards becoming brown and wrinkled. The walls are 
thin in proportion, but hard and firm, and enclose a rather large 
cavity, which communicates with the exterior by a narrow pore 
below, nearly closed by hairs. In the cavity live numerous whitish 
or pale reddish-yellow mites. The galls are readily detected, on 
grasping the leaf, by their hard, shotty feel. Abundant on a 
small bush at Banchory in September. 
F. Hrinewm growths, forming patches }-} inch across, irregular in 
form, situated on the upper surface of the leaf, and then red- 
purple in colour (— Erinewm rosewm Schultz), or on the lower 
surface when the patches are white (— E. betulinwm. Schum.). 
On microscopic examination the patches are found te be composed 
of small, rounded bladders, suddenly contracted below into the 
stalk, and transparent. Among these live numbers of mites— 
Phytoptus—of very small size. The patches are very common 
throughout the summer on leaves of birches, almost everywhere. 
Alnus glutinosa L. (Alder or Arn.). 
A. (— Cephaloneon pustulatum Bremi). Galls scattered over the upper 
surface of the leaves, irregularly obconical, about 3's inch in dia- 
meter, point of attachment very narrow, surface naked, wrinkled, 
reddish-yellow ; central cavity irregular, opening by a small hole 
on the lower surface; tenanted by multitudes of mites—Phytoptus. 
Common throughout the summer everywhere. 
B. Galls on the upper surface of the leaf in the axils of the chief 
veins along the midrib, in pairs divided by the midrib. They ap- 
pear on the upper surface as green or reddish knobs about ;'5 inch 
in diameter, and attached by a very broad base; the surface is 
naked and wrinkled. Below they have a wide opening, nearly 
filled with short, whitish hairs, which extend a little way along 
the midrib and chief vein; among the hairs live the mites—Phy- 
toptus. These galls are as common as the former, and often occur _ 
on the same leaf with them. , 
c. Erineum alnewm. Persoon, caused by Phytoptus. Like most Hrinea, 
it occurs on the lower surface of the leaves, between the veins, 
where it appears as patches, irregular in form, ¢-} inch across, at 
first yellowish-white, but becoming rusty or red round the mar- 
gins, the colour extending gradually all over the patch. To the 
naked eye it seems to be made up of closely-packed little vesicles, 
but under the microscope it is found to consist of membranous 
vesicles much and irregularly lobed, and supported on a thin 
stalk; each lobe ends in a slight dilatation. Among the vesicles 
occur the mites, rather few in number in the examples that I have 
seen. The patches sometimes are large, and nearly cover the 
whole lower surface; on other leaves they are small and scattered ; 
there is a slight projection on the upper surface, opposite the 
growth. Common at Banchory-Ternan in September. 
Nat. OrD. CONIFER. 
Pinus sylvestris L. (Scotch Fir). Galls of Oribata geniculata Latr. They 
are swellings on the branches usually just below the origins of 
the twigs, rarely terminal (sometimes several occur on a branch), 
rounded or elliptical, 1-} inch in diameter; internally they have a 
woody centre, surrounded by swollen bark, in which are numerous 
