Cynips. The galls of verrucosa are strictly leaf galls, the result of the oviposition of the agamic insect in the large terminal buds where the young leaves are fairly well developed, instead of in the undeveloped, adventitious buds patronized by folii and longiventris. Adler averred (1881) that even when the verrucosa galls appear to be on the young shoots, small axillary buds will be found in the angles between the galls and the shoots, evidencing the origin of the gall from young leaves.
The insects of verrucosa are easily recognizable from the bisexual forms of other European Cynips. Schlechtendal's original description (quoted above) is precise in its characterization of the adults, but the descriptions (both of the insects and the galls) in the later European work are poor and evidently not based on actual specimens.
The young galls appear when the buds of the oaks first open, which is late in April or early in May (acc. Schlechtendal 1870) in most of the range of the insect. Adler (1881) reported mature galls by the end of May with the insects emerging late in May or early in June. Schlechtendal's material emerged late in May.
Altho the galls of the agamic divisa are abundant in Central Europe, the collections of the bisexual form have been few, and this is one of the European cynipids that needs further observations. Adler showed that the agamic divisa gives rise to the bisexual verrucosa, but he did not obtain return data. There seems to be no reason for questioning this relation, altho experimental proof of it would be worth obtaining.
Cynips divisa variety atridivisa, new variety
agamic form
Figures 18, 103
GALL.—Apparently not different from that of variety divisa, unless it averages smaller; on Quercus pedunculata.
