INDIRECT INJURIES CAUSED BY INSECTS. 191 



dered disgusting by earwigs that have crept into it, or 

 the green caterpillar of Pontia Rapte. 



Our peas, beans, carrots, parsnips, turnips, and pota- 

 tos are attacked in the garden by the same enemies that 

 injure them in the fields*; I shall therefore dismiss them 

 without further notice, and point out those which infest 

 another of our most esteemed kinds of pulse, kidney 

 beans. These are principally Aphides, which in dry 

 seasons are extremely injurious to them. The fluid 

 which they secrete, falling upon the leaves, causes them 

 to turn black as if sprinkled with soot ; and the nutri- 

 ment being subtracted from the pods by their constant 

 suction, they are prevented from coming to their proper 

 size or perfection. The beans also which they contain 

 are sometimes devoured by the caterpillar of a small 

 moth b . Onions, which add a relish to the poor man's 

 crusts and cheese, and form so material an ingredient in 

 the most savory dishes of the rich, are also the favourite 

 food of the maggot of a fly, that often does considerable 

 damage to the crop. From this maggot (for a supply of 

 onions containing which I have to thank my friend Mr. 

 Campbell, surgeon, of Hedon near Hull, where it is 



a In lately examining, however, some young garden peas and beans 

 about four inches high, I observed the margins of the leaves to be 

 gnawed into deep scollops by a little weevil (Sitona lineata), of which 

 I found from two to eight on each pea and bean, and many in the 

 act of eating. Not only were the larger leaves of every plant thus 

 eroded, but in many cases the terminal young shoots and leaves were 

 apparently irreparably injured. I have often noticed this and another 

 of the short-snouted Curculios (S. tibialis} in great abundance in 

 pea and bean fields, but was not aware till now that either of them 

 was injurious to these plants. Probably both are so, but whether 

 the crop is materially affected by them must be left to further 

 inquiry. b R eau m. ii. 479. 



