NOTES AND QUERIES. 387 



mountain summits as those mentioned above, which are really climatic 

 islands. Dragonflies have a nearly regular patrol system along favourable 

 stretches of path or the shore of a pond, &c. Any one can verify by 

 observation that each has his own little district, and vigorously objects to 

 any one poaching on his preserves ; at least, I certainly believe this : hence 

 it is, perhaps, more surprising that they should have a migration of the 

 same kind. — G. F. Scott Elliot (Newton, Dumfries). 



Insect Migration.— With reference to the article " Migration of Butter- 

 flies," by the Editor, in the current number of 'The Zoologist ' (p. 335), 

 I have for many years been aware of the fact that there is, at irregular 

 intervals, a very considerable immigration of insects across the North Sea 

 to the east coast of England. These are chiefly butterflies, moths, and 

 dragonflies, the latter Libellula quadripunctata. The great movement 

 of Plusia gamma recorded by Herr Gatke in 1882, in August, across 

 Heligoland, coincides with the appearance of immense numbers of the 

 same insect on the coast districts of Lincolnshire and Yorkshire; this 

 immigration was recorded by me in ' The Field ' of Sept. 16th of that 

 year. Few naturalists are aware with what apparent ease butterflies and 

 moths cross an immense extent of water. I have seen from the cliffs 

 of Heligoland the common Cabbage Butterfly drifting in from the east, 

 some to alight, but the majority passing north and south of the island, and 

 going west like so many flakes of snow. When in the middle of the North 

 Sea I have also seen them pursuing the same course, and crossing close 

 before the bows of the vessel without attempting to alight. During the 

 autumn of 1894, about twenty-four examples of that lovely insect, Sphinx 

 convolvuli, were taken in the Spurn district, and many more seen ; these 

 were probably immigrants. Many years since I recollect considerable 

 numbers were washed up dead between Kilnsea and the Spurn. The 

 amazing numbers of Vanessa urticaz which have appeared during the 

 present autumn, especially in east-coast districts, may perhaps be accounted 

 for by a great migration across the North Sea; but of this further proof is 

 needed. 1 have seen them this year, in September, by hundreds, over the 

 flowers in small gardens in a town near the coast, where in former years 

 single examples would scarcely have appeared.— John Cordeaux (Great 

 Cotes, Lincolnshire). 



Insect Migration. — For some years past I have carried on a series of 

 observations at and near the Spurn Point on the Holderness coast, which 

 leaves no doubt in my mind, and that of other observers with me, that 

 there are erratic immigrations of some insects, at irregular intervals, from 

 time to time. This opinion has been more thau ever strongly forced upon 

 me this month and last (Aug. and Sept.) by the sudden appearance on the 

 Holderness coast of several insects in such numbers as almost to preclude 



