THE ENTOMOLOGIST. 27 
It is generally about the size of, and has very much the 
appearance of, a large gall of Cynips lignicola. At first it is 
greenish, but when mature of a yellowish clay-colour, some- 
times almost black. It is sprinkled all over with small 
Fig. 36.—GaLut or SYNOPHUS POLITUS. 
whitish warts, and covered with short hairs, which are only 
visible with the aid of a magnifying-glass (sometimes the 
base, which generally retains the bud-scales, is fixed to, and 
grown into, the branch). At the point opposite the base 
either a small umbilicate cavity or a small conical tubercle 
is often found. The section shows that the gall consists of 
two layers: the exterior one is green when fresh, and consists 
of bark substance; the interior one, however, which contains 
the larva-cell, is formed of trne wood substance. As the 
second variation, 1 might mention that form which bears 
crippled leaves on its surface, but in all other respects 
perfectly agrees with the former variety. From this second 
variation a third form is very often developed: in this case 
the gall appears to have so long a continuity that it could 
easily be mistaken for a mere swelling of the stem (con- 
sequently it does not look like a bud-gall); this delusion is 
all the more easy if the fly is not developed the first year, and 
the following year the gall continues to grow asatwig. A 
fourth variety is interesting on account of the constancy of its 
size and shape; we often meet with an oak on which we only 
find this variety in great numbers: it is spherical, and is 
about five millimetres in diameter; the small white warts are 
wanting, or are far less conspicuous than in the first-described 
form; the umbilic or conical projection at the top is also 
wanting. In section it exhibits a much thinner layer of bark 
and wood substance, while respectively the larva-cell is very 
