INSECT " BLIGHTS AND BLESSINGS.' 



129 



the Green Fly, whose dried skin then forms a protection to the 

 chrysalis of the parasitic Fly, which when mature bites a circular 

 hole in the skin (fig. 23) and escapes to continue its species in 

 due course. There is a large field open to anyone desirous of 

 studying the parasitic Hymenoptera of the British Aphida?. 



If I did not know it to be a fact, I should not venture to say 

 that the disease known as " The Black Currant Gall " is utterly 

 unknown to a large number of gardeners having hundreds and 



Fig. 21. 



thousands of trees under their care ; and yet every bush has 

 been more or less affected, the common excuse for the scarcity 

 of fruit being " Oh ! the birds take them." It is not to be 

 expected that gardeners should know the Gall Mite, which is but 

 the one four -hundredth part of an inch long ; but every gardener 

 in Great Britain ought to know the " gall " itself — a sketch of 

 which I give at figs. 24 and 25 — a photograph of twigs showing 

 innumerable galls of from a quarter to three -eighths of an 

 inch in diameter, much resembing a hard-hearted cabbage. 



