432 THE ENTOMOLOGIST. 
and, in process of time, is developed again into leaves. In 
other cases the circle of existence is less simple, and two 
circles of life are combined ; and some part of the substance 
of the oak-leaf is transformed into oak-spangles by means of 
a gall-fly. In the oak-currant the circle is more complicated, 
for not only gall-flies, but also parasitic flies take part in the 
work. In the oak-apple the arrangement is far more intricate, 
for very numerous kinds, perhaps one hundred in number, 
representing all the chief orders of insects, are occupied in 
it; and it is not only inhabited by insects, but is also 
frequented by Acari or mites, whose chief dwelling-place is 
wood-moss, where the species of Bryobia, Zetes, Tydeus, 
Iphis, Murcia, Nothrus, Oribates, Pelops, Penthaleus, Hoplo- 
phora, Eumeus, Erymeus, Caligonus, Carabodes, Celzno, 
Cepheus, and the more elegant Eupodes and Linopodes 
abound; and British Entomology is in need of a book on 
these wood-moss mites; and oak-apples afford abundant 
materials for another volume. Teras terminalis, by means of 
its punctures and egg-laying, is the means of forming the 
oak-apple, which supplies its offspring with board and 
lodging; but numerous enemies appropriate to themselves 
the bodies, or the food and habitation, of this offspring ; and 
other kinds avenge the Aborigines by consuming their 
invaders. Some kinds inhabit the oak-apple for two months ; 
one species lives a year in it; and the successive generations 
of this fly pass from oak-apple to oak-apple. But the life- 
history of the other kinds requires to be traced for ten months 
elsewhere. Each oak-apple is tenanted by many individuals 
of the Teras, and there is much to be observed as to how the 
grubs are distributed through the oak-apple during its 
growth, and in noticing the successive arrival of other 
species, which find their way into the oak-apple, or insert 
their eggs therein. In conclusion I will mention two or three 
oak-apple insects, in addition to those which | have previously 
noticed. Lampronota Segmentator:—this is probably a 
parasite of Poecilochroma corticana (Fam. Tortricide), a 
moth that frequently emerges from oak-apples. Psylla : 
—I have not yet ascertained the name of this species; it has 
a very close resemblance to P. Buxi. Anthomyia pluvialis :— 
another species of this genus, A. canicularis, has been reared 
from the cottony oak-gall, the habitation of Aridricus Ramuli. 
