74 THE ENTOMOLOGIST. 
solitary, it may be easily distinguished by always occurring 
on the bark of the Turkish oak (Quercus Cerris) in the form 
of knobs, varying in size from a hempseed to a walnut. Ifa 
specimen be detached from the twig it may be plainly seen to 
have been growing on the woody part, seated on a very short 
pedicle, and to have raised up the bark in its immediate vicinity. 
It is found singly on the most slender young shoots, in the form 
of aspherical knob, or occasionally it has so enclosed the 
twig that its protruding sides meet exactly opposite the point 
of its attachment. On the larger twigs we find a great number 
of these galls so crowded together that each becomes flattened 
at the point of contact, and the mass thus formed surrounds 
the twig in the form of an irregular band, that sometimes 
extends to three centimeters in length and thickness. The 
longitudinal fissure in the bark, through which these galls 
have forced their way, may be readily perceived if one of the 
size of a hempseed or a pea has happened to remain unde- 
veloped, and to grow separately on a thicker twig. The galls 
appear at midsummer, and are of a light green colour, and 
more or less clothed with a short tomentum; later in the 
autumn they assume a brownish yellow hue, and lose their 
tomentum, more especially the larger ones, whilst the imma- 
ture specimens often retain it. ‘The interior of the gall 
consists of a rather loose parenchyma: it is hollow in the 
centre, and contains a moderately large, oval, inner gall, 
which is seated at or near the base of the outer one; some- 
times this is quite detached, at others it is loosely adherent to 
the substance. In the smaller specimens, which only contain 
parasites, this inner cell is not developed, and we frequently 
find, as in several other species of galls, little oval cavities, 
arranged in a radiating manner in the parenchyma, and these 
serve as homes for the parasites. This gall is not deciduous, 
and specimens two or three years old, and partly destroyed, 
may be often met with on twigs. The perfect insect emerges 
in December of its first year—G@. ZL. Mayr. 
Cynips cerricola is accompanied by four inquilines, and 
the distinctive characters of these, and of others of their tribe, 
may be noticed on another occasion :—(1) Synergus variabilis 
of Mayr—it appears from March to July in the second year; 
(2) Synergus thaumacera of Dalman—April, second year; 
(3) Sapholytus undulatus of Mayr—it appears in May and 
