INDIRECT INJURIES CAUSED BY INSECTS. 157 



Mr. Westwood, great injury was done in the market gardens 

 to the west of London to the cauliflowers and other plants of 

 the cabbage tribe by a species of aphis covered with a purple 

 poAvder, which had not been before observed by the gar- 

 deners who called it a new kind of blight. ^ 



Our peas, beans, carrots, parsnips, turnips, and potatoes 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 prin- 

 cipally 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 nutriment 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.'^ — 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 



1 Trans. Ent. Soc. Lond. ii. proc. xxi, 



2 On examining some young garden peas and beans about four inches high, 

 I observed the anargins of the leaves to be gnawed into deep scollops by a little 

 weevil {Sitonalineata), 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. Garden beans still more than the field kinds, Mr. 

 Curtis informs us, greatly suffered in 1841, from the holes which humble-bees 

 (^Bombus terrestris and lucorum) made in the blossoms (as they usually do) to 

 get out the honey contained in the nectary, which operation injuring the pods 

 in their earliest state, four-fifths of them were destroyed, and produced no beans. 

 (Curtis in Gardeners Chron. 1841, p. 485.) When at Shrewsbury in August 

 1839, I found almost every pod of the garden peas brought to market, inhabited 

 by a single yellowish-white lepidopterous larva, three or four lines long, which 

 had eaten more or less of each pea, but which, though several assumed the pupa 

 state and entered the earth in the box in which they were placed, never became 

 perfect moths. 



3 Reaum. ii. 479. 



