68 
the galls. They occur at Braemar, where Dr White first detected 
them. The same species of midge produces similar galls in Perth- 
shire on Polygonum Persicaria L., and on P. amphibwum L., but I 
have not seen specimens on either plant from this district. 
Nat. OrpD. UrTICEs. 
Urtica dioica L. (= Common Nettle), galls of Cecidomyia Urtice Perris. 
The gal!s chiefly occur on the leaves at the apex of the stem, one 
on each side of the midrib at the base of the leaf; sometimes they 
occur on the leafstalks or on the peduncles of the flowers, or 
sometimes the apex of the stem bears a mass of them. They are 
irregularly globular, about + inch in diameter, brownish-green 
above, pale green below, rough and hairy, fleshy, and contain a 
single cell, usually occupied by several white larvee. When the 
galls are situated on the leaves they project from both surfaces. 
They are abundant everywhere. 
Nat. OrD. SALICINE®. 
Populus tremula L. (—Aspen) A., galls of Cecidomyia (Diplosis) Tremule 
Winn. They form swellings on the petiole anywhere from its 
base to where it joins the blade of the leaf, sometimes even 
encroaching on the leaf blade; they are seldom situated on the 
twigs. They are irregularly rounded, about 4 inch in diameter, 
more or less tapering at the ends, and usually more projecting at 
one side; the surface is smooth, and reddish or yellowish green; 
the sides are thick, hard, and woody, and the cell is rather small ; 
when the larva is mature the gall splits open atthetop. The 
galls are not scarce in the Den of Maidencraig, near Aberdeen, 
in Glen Gairn, and in Braemar in July and August. 
Galls of Phytoptus (= Heliazeus Populi Kirch.). They are situated 
in pairs on the upper surface just where the leafstalk joins the 
leafblade, less often they stand singly or in threes; they are irre- 
gularly rounded, 7's-12 inch in diameter, surface naked, wrinkled, 
and green or reddish brown ; the walls are fleshy, and enclose an 
irregular cavity in which live multitudes of the mites. , I have 
found them common at Ballater, in Glen Gairn, and in Braemar 
throughout summer. 
. Galls of Batoneus Populi, Kirch. They form irregularly rounded 
masses 3-3 inches in diameter, attached tothe branches at the base 
of young twigs, or to the trunk underground. When fresh they 
are green or red, are covered with a downy pubescence, and are 
rather fleshy; after a time they become hard, dry, and friable ; 
they contain many irregular cavities in which live multitudes of 
the mites. These galls are common during the summer in Brae- 
mar, and at Inver, near Balmoral. 
. Erinewm growths on the leaves on the lower surface (= Erinewm 
Populinum, Pers.), indicated on the upper surface by one or more 
raised blisterlike yellowish-green patches, readily seen. On the 
under surface is a recess lined with short hairs(reddish or brownish 
in colour), among which live mites, Phytopti. Affected leaves are 
abundant at Inver, near Balmoral, in August. 
Salix fragilis L. (= Crack Willow, or Withy \ Galls of Nematus gallicola, 
” 
alba L. (= White Willow) West. and Steph. 
(vide Sc. Nat. II. pp. 11-15, pl. 1). The galls are very noticeable 
on the leaves, either singly or in a row along each side of, but 
not touching, the midrib; they are oval, usually about 4X4 inch, 
and project chiefly below; the central cavity is at first small and 
