1826 ARBORETUM AND FRUTICETUM. PART III. 
winged state, ready to take advantage of the first warm day to burst forth 
from their prison. This gall, which is the largest excrescence that we have 
hitherto seen formed by any cynipideous insect, is irregularly oblong, and nearly 
5in. in length: it is 11 in. in diameter in the thickest part, the general thickness 
being about lin. : its appearance is that of a piece of very fine-grained sponge. 
On making a section ]}in. long by lin. broad, between 60 and 70 cells, 
closely packed together, and of an oval form, were discovered, each containing 
a single cynips. Taking the size of the entire gall into consideration, it 
must contain, at thelowest calculation, upwards of a thousand individuals, the 
produce, probably, of a single female cynips. » The perfect insect is of a pale 
brownish colour, witha shining red abdomen, having two small dorsal black spots 
at the base. This gall was unknown to Réaumur, having been first described and 
figured by Bosc. (Journ. de Physique, 1794.) A figure, apparently of the same 
gall, is given in the Insect Architect., p.385.; but it is there erroneously 
stated that the inhabitant is identical with the cynips of the oak apple (C. 
quércus terminalis) ; and this is supposed to be accounted for by the observa- 
tion, that the root galls are “ probably formed at a season when the fly 
perceives, instinctively, that the buds of the young branches are unfit for the 
purpose of nidification.”. Numerous other excrescences, and some most 
curious distortions, seem to be the result of the attacks of insects on the 
buds or branches of the oak in their embryo or infant state, of which the 
coadunate stems and witch knots are among the most remarkable; but it is 
doubtful whether many of these monstrosities are not idiopathic diseases of 
the tree. 
The oak leaves, also, are occasionally observed covered with numerous 
galls of small size, and evidently belonging to different species, being of dif- 
ferent forms, of some of which the insect has not 
yet been discovered. Several of them are figured 
by Réaumur. (Mémoires, tom. iii. pl. 35. fig. 3, 
4, and 6., pl. 40. f. 13—15.) Some of these 
are of a larger size (fig. 1651.) ; not more than 
three or four being found upon a single leaf 
(Rosel Ins. Belust. Suppl., tab. 69.); whilst 
others, which are as large as a boy’s marble, 
and perfectly globular, are often found singly 
upon the leaves ; the last being produced byC. Y 
quéreus folii. (Réaum. Meém., tom. iti. pl. 39. ly os) 
fig. 13—17., pl. 37. fig. 10, 11., pl. 40. fig. 8.) % 
It is a curious circumstance connected with 
these large globular galls (and which is also 
observed in the gall nut), that, notwithstanding 
the large size of the galls, only a single insect is 
enclosed therein; so that a very small portion 
only of the centre of the gall is consumed, the 
cynips arriving at its perfect state within its 
small central prison, out of which it has to cut 
its way through a great portion of the solid sub- 
stance of the gall. The surface of the majority of these galls is smooth; 
some, however, are imbricated, and others are clothed with a woolly kind of 
down, similar in its nature to the outside of the bedeguar of the rose. A gall 
of this kind is figured in the Insect Architecture, p. 388., found upon the twig of 
an oak; and in Dr. Nees von Esenbeck’s collection of minute Hymenoptera, 
at present in Mr. Westwood’s possession, there is a similar gall, of small size, 
upon an oak leaf, with the cynips by which it is produced (C. quércus lanata 
Necs MSS.). 
Oak Spangles. Amongst the excrescences found upon the leaves of the oak, 
are to be noticed the reddish insular scales on the under side of the oak leaves 
mentioned by Mr. Lowndes (Gard. Mag., vol. xi. p. 691.), and supposed by 
him to be parasitic plants. When full grown, they are about one eighth of an 
