DESTRUCTIVE INSECTS. 295 



other insects. If they are favoured by dry and fine 

 weather about the end of June they will seize the 

 tender tops of field peas in such numbers, that the 

 crop vanishes before them as if scorched by fire ; and 

 when the podless straw is cleared off, the ground is 

 literally covered with their dead and dying remains, 

 together with the sloughs they throw off during their 

 short life. For such visitations there is no remedy ; 

 but in gardens whether they breed on plants in or 

 out of doors, they are quickly dispersed by the smoke 

 of tobacco. 



Cynips or Gallfly. These insects may be noticed 

 not so much for the damage they do the plants on 

 which they breed, as for the curious transformations 

 produced on the members of the plant charged with 

 their ova. If we examine the large imbricated galls 

 on the extremities of the shoots of the oak, or the 

 large and small globular galls called oak-apples, on 

 the under side of the leaves, we cannot but admire 

 the instinctive sagacity of the parent fly, and the 

 curious expansion of the cuticle, the enlargement of 

 the parenchymous integument under it, and the 

 persisting functions of the sap vessels to supply a 

 monstrous dilatation of all the parts immediately 

 surrounding the inserted egg. As this soon becomes 

 a maggot, daily advancing in size, so is the gall in 

 bulk till the chrysalis is formed; soon after which, 

 the last transformation takes place ; the perfect 

 insect eats its way through its parenchymous cradle, 

 and launches into the open air. The perfect rotundity 



