Ixxxviii. PRESIDENT'S ADDRESS. 



The second form of migration of Aphides is much more 

 generally known, and is probably familiar to many of the 

 members of our Club. The most abundant form of, at all 

 events, some of the commoner species of Aphis, is a wingless 

 one, and the rate at which these insects increase is something 

 extraordinary, even for insects. But under certain circumstances, 

 notably a continued drought or lack of green food, winged forms 

 are developed, and at times these give rise to clouds of the 

 insects flying in the air in countless millions. Such swarms are 

 not uncommon, but I am not aware that any definite destination 

 has ever been proved to exist for them. They, and also, I think, 

 many other dark and misty states of the air with which they have 

 no connection, go by the common name of a " blight." When 

 I have seen these swarms, they have appeared to me to be rather 

 hovering aimlessly in the air than pursuing any definite course, 

 but there are many records of enormous masses of their dead 

 bodies being found on sea coasts, carried there, I believe, by the 

 wind, and not by their own desires. Gilbert White gives an 

 account of a swarm at Selborne on August ist, 1785, which 

 covered everything with a black coating. And there is a record 

 of a mile of beach between Bournemouth and Poole being 

 covered with a green line of Aphis bodies at high-water mark. 

 There are also records of these swarms being accompanied by 

 species of Coccinella or ladybirds, which devour them, and of 

 flies of the family Syrphidce, the larvae of which prey upon 

 Aphides, the eggs being laid on leaves tenanted by colonies of 

 them. 



ORTHOPTERA. 



Though, fortunately, in this favoured country we rarely see 

 even isolated individuals, and never suffer from their attacks, 

 yet both in the Old and New World the migratory insects most 

 dreaded by and most injurious to man are certain species of the 

 locust tribe. The migrations and depredations of these insects 

 have been the constant theme of writers, and a volume might be 



