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, Eumseus, Erymasus, Caligonus, Carabodes, Celaeno, 

 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 ofl'spring 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 nmch 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 I have previously 

 noticed. Lampronola Segmentator: — this is probably a 

 parasite of Pcecilochroina corticana (Fam. Tortricida)), a 



raoth that frequently emerges from oak-apples. Ps}lla : 



— l*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. 



