is precisely in accordance with the proceedings of Osmia bicomis. There is a remarkable peculiarity in the relative sizes of the sexes of this insect, the males are considerably larger than the females, in some instances twice the size ; this peculiarity does not occur in any other species of British bee. Time of appearance June and July.
List of Insects inhabiting Oak-apples.
The well-known oak-apples are inhabited by a great variety of insects, which con- stitute a little world, and derive their nourishment either immediately or indirectly from those galls. The insects in the following list have emerged from a considerable number of oak-apples collected in the neighbourhood of Southgate during the sum- mer of 1846.
June, 1845.
Nitidula grisea, 1
Balaninus glandium ? 149 during this and the following months of summer
Forficula auricularia, a few in the summer, some of them were larvae
Psocus subocellatus ? a few in the summer and autumn
Atropos ? abundant till the winter
Teras Quercus-terminalis, 495
Synergus socialis, 27. A few specimens of two or three other species of Cynipites appeared in the summer
Pteromalus Naubolus, 7 females
Pteromalus ? 2 males. Nearly allied to the preceding species
Pteromalus semifascia, 1 female
Pteromalus ovatus, 5 males
Pteromalus domesticus, 6 or 7 females during the summer
Eupelmus urozonus, 4 females
Eulophus gallarum, Nees, 1 (E. Euedoreschus, Walker, Mon. Chal. i.)
Cecidomyia ? 1
Cecidomyia ? 2
Tortrix viridana, 2 or 3*
July
Physoevria ? 2 or 3
Nitidula grisea, 1
Lalridius lardarius, 1
Corticaria transversalis, 2
Carpalimus fuliginosus, 1
Aleochara ? 2
Orchestes Quercus, 4
Pimpla ? 1
Pimpla ? 1
Hemiteles areator, I
A large caterpillar, probably of a Noctua, sometimes consumes the whole interior of the oak-apples.
