Page:The American Cyclopædia (1879) Volume XII.djvu/573

 OAK APPLE OAKLAND 559 left in hatching; but the larva, or young gall insect, seems rather to be gradually trans- formed from the egg. This larva is whitish, very soft, and has an inconspicuous head and American Oak Apple, showing internal structure, the grub in the central cell, and the hole on the side through which the perfect fly issues. no legs. The body is more or less cylindrical, tapering to both ends, but more especially be- hind, and lies in a curved position within its cell. As the larva grows the gall substance around its cell hardens into a cream- or buff- colored shell, which partially separates from its surroundings. This separation may perhaps be in part explained by the absorption of di- gested matter, as no faeces are found in the cav- ity, and, if excreted and absorbed, they would naturally cause increased hardening, and lessen the influence of the plant immediately around the cavity. The pupa state is gradually assum- ed, and the fly attains perfection and remains in its cell for some time before eating its way out to liberty through the walls of its gall ; all the transformations being less sudden than in the majority of insects, on account of the del- icacy of the successive skins to be thrown off. The American oak apple begins to develop as Bastard Oak Apple. soon as the leaves put forth in spring, and when mature has a shiny, rather smooth, dingy buff- colored exterior, the space between the central cell and the external rind being filled with a 613 VOL. xii. 36 drab-colored spongy mass, which becomes more solid and paler toward the centre. The insects issuing from this gall in early summer are of both sexes, and have been described as cynips q. spongifica ; those issuing from it in the fall, and which have been described as (7. q. acicu- lata, are larger and otherwise different, and are all females. There is another large gall found exclusively on the red oak (Q. rubrd), which is called the bastard oak apple. It differs from the genuine American oak apple in having the central cell connected with the rind by slender radiating filaments instead of spongy matter. The insects produced from this gall, and described as cynips q. inanis, are undis- tinguishable from the bisexual flies produced in early summer from the genuine American oak apple; a fact of great biological significance, which indicates that these galls, though so very different in structure, may be specifically rela- ted. These oak apples are (as are indeed all galls) the result of the combined action of an animal and a vegetal organism, and must ne- cessarily cease to exist if either of the organ- isms which cooperate to produce them -were swept from existence ; yet the study of galls belongs to the entomologist rather than to the botanist, and those of this country have been investigated especially by Baron Osten-Sacken, H. F. Bassett, Prof. 0. V. Riley, and the late Dr. Harris and Mr. B. D. Walsh, whose dis- coveries present some of the most remarkable facts in insect biology, and afford striking ex- amples of dimorphism, of parthenogenesis, and of alternation in generation. Not all the in- sects found in oak apples are gall flies ; parasi- tic insects deposit their eggs in the forming ap- ple, and their larvae live at the expense of the grub of the true gall maker. Several species, called inquilineSy devour the gall substance at the peril of the young of the true architect; while others take possession of the old and deserted galls. OAKELEY, Frederick, an English clergyman, born in Shrewsbury, Sept. 5, 1802. He gradu- ated at Oxford in 1824, became a fellow of Balliol college in 1825, prebendary of Lichfield in 1832, chaplain to Lord Stanhope in 1834, and "Whitehall preacher for Oxford in 1837. In 1845 he became a Roman Catholic, and in due time was ordained priest and appointed missionary rector of St. John's, Islington, and in 1852 canon of Westminster. Among his numerous works are: "Whitehall Sermons" (1839) ; "A Letter on submitting to the Cath- olic Church" (1845); "Practical Sermons" (1848); "Order and Ceremonial of the Most Holy and Adorable Sacrifice of the Mass" (1848; 2d ed., 1859; translated into Italian); " The Church of the Bible " (1857) ; " Histori- cal Notes on the Tractarian Movement, A. D. 1833-'45" (1865); "Letters on Dr. Pusey's Eirenicon" (1866); "Lyra Liturgica" (1867); and " The Priest on the Mission " (1871). OAKLAND, a S. E. county of Michigan, drain- ed by branches of the Clinton and Huron riv-