THE CANADIAN ENTOMOLOGIST. lo 



The caterpillars tunnel the pulp of the fruit in every direction, leaving 

 brown-coloured channels with rather large chambers here and there ; this 

 attack thus being easily distinguishable from that of the common 

 codling worm. 



According to Mr. Fletcher, this apple pest has not previously been 

 noticed in America, and Lord Walsingham, of Thetford, England, that 

 well-knov/n microlepidoj)terologist, to whom a specimen was sent for 

 determination, states that Argyresthia conjugella in Europe feeds on the 

 fruit of Pirns ( Sorbiis) aiiaiparia, but has not been recorded from Pirns 

 mains. At least no injury of this insect on apples has, as far as I know, 

 until now been observed in Europe. 



Last summer, however, an apple pest, quite similar to that described 

 by Dr. Fletcher, has been injuriously abundant in Finland, the apple 

 fruits in almost every orchard having been very seriously injured by 

 small caterpillars and often completely spoiled for use. There can be 

 little doubt that these caterpillars are the larvae of Argyresthia coiijugella, 

 one of out commonest tineids. 



The unexpected and violent attack of an insect, not previously 

 known in Finland as an enemy to the apple fruit, is peculiar enough, but 

 I think it will be a matter of still greater interest, since we may be able 

 to point out the cause of this phenomenon. 



The caterpillar, as stated above, ordinarily feeds in our country on 

 the fruits of the Mountain Ash ( Sorbns ancuparia), and sometimes also 

 on those of the Bird Cherry ( Pruiius padus). In 1896 and 1897, 

 especially in the latter year, the Mountain Ashes bore fruits in uncom- 

 monly great abundance, which was an extraordinarily great advantage 

 for the multiplying of the insect. But this summer the fructification of 

 the Mountain Ash, as well as of the Bird Cherry, almost totally failed 

 throughout Finland. The insect could Jiot find its ordinary food, it must 

 try to obtain another, and the egg-laying moths, swarming in immense 

 numbers, instinctively flew to the apple trees to lay their eggs. 



In a letter recently received, Ur. Fletcher informs me that this 

 insect during the past season was again very destructive to fruits in 

 British Columbia, and, although he could not confirm it, he was told that 

 the prunes were attacked as well as the apples. If this were really the 

 case, the fact stated above, that the larvae attack also the Bird Cherries, 

 seems to be of considerable interest. 



