THE ENTOMOLOGIST. 22] 
old galls may be found on the trees, and some even adhere 
after they have lost all the leaves. They then exhibit the 
opened, unprotected inner galls, surrounded by prickly 
projections.—G. L. Mayr. 
The gall of this species occurs only on Quercus cerris, 
consequently is not known as British. From it Ceroptres 
Cerri, Mayr, and Megastigmus dorsalis, /abr., may be bred 
in July of the same year; the latter commonly. Synergus 
evanescens, Mayr, is another inquiline occurring in the 
following April; and Callimome regius, Nees, a parasite. 
Dr. Giraud says “the caterpillars of Grapholita amygdalana 
live frequently in these galls, feeding on the exterior substance, 
and even on the cellules when they are young enough.” This 
Tortrix has also been bred from galls of Lignicola or 
Kollari.—2Z. A. Fitch. 
The peculiar Relations of Plants and Insects as exhibited 
in Islands.* By ALFRED R. WALLACE, Esq., F.L.S., &c. 
Ever since Mr. Darwin showed the immense importance of 
insects in the fertilisation of flowers great attention has been 
paid to the subject, and the relation of these two very 
different classes of natural objects has been found to be more 
universal and more complex than could have been anticipated. 
Whole genera and families of plants have been so modified as 
first to attract, and then to be fertilised by, certain groups of 
insects; and this special adaptation seems in many cases to 
have determined the more or less wide range of the plants in 
question. It is also known that some species of plants can 
be fertilised only by particular species of insects, and the 
absence of these from any locality would necessarily prevent 
the continued existence of the plant in that area. Here, I 
believe, will be found the clue to much of the peculiarity of 
the floras of oceanic islands, since the methods by which 
these have been stocked with plants and insects will be often 
quite different. Many seeds are, no doubt, carried by oceanic 
currents; others probably by aquatic birds. Mr. H. N. 
Moseley informs me that the albatrosses, gulls, puffins, tropic 
* Part of the President's Address, in Section D (Biology), at the recent 
Meeting of the British Association, 
