THE BLACKTHORN. 



253 



colour wliicli appears when the plum is in blossom. 

 As soon as the Hower-buds of the plum-tree begin 

 to expand, the fly cuts obliquely with its saws 

 into the calyx of some of the larger kinds, and 



deposits its egg. In the course of a few" days 

 the larva is hatched, and immediately leaving its 

 birth-place, w^here there is no suitable food for 

 it, hastens to the minute plum growing near it, 

 and fixes itself to the centre of the stone, w^hich, 

 being tender and milky, affords it the best nourish- 

 ment. The plum meanw^hile continues to grow, 

 and the insect with it. In about six weeks, by 

 which time the larva has attained its full size, the 

 fruit and its destroyer fall together to the ground, 

 when the latter buries itself in the earth, prepares 

 its winter habitation, and emerges in the following 

 spring a perfect insect. 



So great is the mischief wTOUght by these flies, 

 that they sometimes leave not a plum on the trees. 

 In the year 1822, when their ravages w^ere very 

 extensive, Schmidberger had the plums on a Mag- 

 num-bonum tree, which promised to be very pro- 

 ductive, counted : the number, amounted to eight 

 thousand 1 Only three plums arrived at perfection. 



Tentliredo morio — Plum Saw-fly. 

 The line underneath denotes the natural size. 



