varieties folii and longiventris) which seems to me distinctive in the several hundred insects I have examined. The bisexual females of folii and longiventris are to be distinguished on nothing more than the minor leg color characters noted by Adler, altho I find these characters apply definitely for the females (hardly for the males) which I have seen.
Central European folii and longiventris, then, are so completely physiologic species that from insects alone they would never have been separated. On the other hand, as if by deliberate contrast, the insect of the Finnish variety of longiventris is very different in structure from the Central European longiventris altho physiologically (in gall-producing capacities) it is not distinct.
The brilliantly banded galls of longiventris have probably invited many analogies in the minds of all of us, but it remained for Thomas (1897) to publish the suggestion that the galls actually "mimic" the banded shells of snails of the genus Helix, thus discouraging birds which are in search of insects. Such an extension of the natural selection hypothesis almost discourages serious attempts to evaluate the number of cases in which adaptation may have been a real factor in directing the course of evolution. Küster (1911:400) similarly protests against Thomas' paper.
The known biologic data for longiventris apply almost entirely to the typical variety, under which the records are given in detail. Both the bisexual and agamic generations are known for that variety as the result of Adler's experimental work (1881).
Cynips longiventris variety longiventris
agamic form longiventris Hartig
Figures 17, 83, 97, 122, 130-132
[no name] Malpighi, 1686, De Gallis: 21, line 19, fig. 19 [acc. Màssalongo, 1898, Malpighia 11:17].
Cynips longiventris Hartig, 1840, Germar Ent. Zeit. 2: 181, 188 (♀, ⊕). Hartig, 1843, Germar Ent. Zeit. 4:406. Ratzeburg, 1848, Ichneum. Forstins. 2:217. Ratzeburg, 1852, Ichneum. Forstins. 3:254. Schenck, 1865, Jahrb. Ver. Nassau 17-18:157, 175, 179, 223, 226, 250 (♀, ⊕). Reinhard, 1865, Berliner Ent. Zeit. 9:6. Taschenberg, 1866, Hymen. Deutschi.: 144. Schlechtendal, 1870, Stettiner Ent. Zeit. 31:380. Müller, 1870, Ent. Month. Mag. 7:108. Karsch,
