YORKSHIRE GALLS. 
S. L. MOSLEY, F-.E.S., 
Beaumont Park Museum, Huddersfield; Author of ‘ British Birds, Nests, and Eggs,’ etc. 
I am working up the subject of Galls, particularly those of Yorkshire, 
and as there must be a large number still unknown to me, I append 
below a list of such as I have been able to discover, in the hope that 
it may induce persons who come across these curious vegetable 
e€xcrescences to send me anything not mentioned in this list. I have 
included both galls and pseudo-galls—that is, those which com- 
pletely enclose the inmates and those which only partly do so. 
I have appended an asterisk to such species as I have reared the 
perfect insect of, and I shall be pleased to correspond with Yorkshire . 
or other naturalists interested in the subject. 
On Acer campestre, | 
Leaf studded over on face with red pimples. Caused by a mite 
(Phytoptus aceris), Very common. 
On Alnus glutinosa. 
Brown warts in axils formed by midrib and side veins. Caused 
by a mite (Phytoptus). Generally common. This Phytoptus 
has not been named, and I purpose calling it P. axddlarts. 
On Betula alba. 
*Leaf-buds much swollen, never expand, but develop into clusters 
of small twigs known as ‘witch knots.’ Caused by a mite 
(Phytoptus betule). Generally common. 
Small swelling on leaf, showing on both sides. I am unable to 
find any description of this gall, which I find commonly in 
Butternab Wood, Huddersfield. Each gall contains a larva 
of a Cecidomyia? 
On Centaurea nigra. 
*Flower-head hard and woody, with several cells, each containing 
a larva of a two-winged fly (Urophora solstitialis). Whitley, 
near Huddersfield. Mr. Fitch very kindly named the flies 
for me. 
On Corylus avellana. 
*Leaf-buds much swollen, andgnever expand. Caused by a mite 
(Phytoptus coryli). Common. 
On Crategus oxyacantha. 
*Rosettes of leaves at end of shoots. Caused by a midge 
(Cecidomyia crategi). Very common. 
