THE ENTOMOLOGIST. 221 



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, Fabr., may be bred 

 in July of the same year; the latter commonly. Synergus 

 evanescens, Mayr, is another inquiline occurring in the 

 following April ; and Callimorae 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.— i;. A. Filch. 



The peculiar Relations of Plaids 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 diflferent. 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, iu Section D (Biology), at the recent 

 Meeting of the British Association, 



