INDIRECT INJURIES CAUSED BY INSECTS. 103 



many of them, they may seem to be defended by the earth that covers them, 

 do not escape the attack of insect-enemies. The carrot, which forms a 

 valuable part of the crop of the sand-land farms in Suffolk, is often very 

 much injured, as is also the parsnip, by a small centipede (Geophilus elec- 

 lricus),and another polypod (Polydesmuscomplanatus), which eat into various 

 labyrinths the upper part of their roots ; and they are both sometimes 

 totally destroyed by the maggot of some dipterous insect, probably one of 

 the Mnscidce. I had an opportunity of noticing this in the month of July, 

 in the year 1812, in the garden of our valued friend the Rev. Revett 

 Sheppard, of Offton in Suffolk. The plants appeared many of them in a 

 dying state ; and upon drawing them out of the ground to ascertain the 

 cause, these larvae were found with their head and half of their body im- 

 mersed in the root in an oblique direction, and in many instances they had 

 eaten off the end of it. 1 The larva of a little moth (Hcemilis daucella), 

 described by Bouche, feeds upon the seeds both of the carrot and parsnip, 

 covering the umbel with a silken web, and in some years destroys the 

 whole crop. 2 



America has made us no present more extensively beneficial, compared 

 with which the mines of Potosi are worthless, than the potato. This in- 

 valuable root, which is now so universally cultivated, is often, in this 

 country, considerably injured by the two insects first mentioned as attack- 

 ing the* carrot, and also by the wire-worm. The Death's-head hawk-moth 

 (Ackerontia Atropos) in its larva state feeds upon its leaves, though without 

 much injury. In America it is said to suffer much from two beetles 

 (Cantharis cinerea and vittata), of the same genus with the blister-beetle 3 ; 

 and another species, C. verticalis, in 1839, wholly destroyed the leaves of 

 the crops at Volterra in Tuscany. 4 In the island of Barbadoes some 

 hemipterous insect, supposed to be a Tettigonia, occasionally attacks them. 

 In 1734 and 1735 vast swarms devoured almost every vegetable production 

 of that island, particularly the potato, and thus occasioned such a failure 

 of this excellent esculent, especially in one parish, that a collection was 

 made throughout the island for the relief of the poor, whose principal food 

 it forms. 



The chief dependence of our farmers for the sustenance of their cattle 

 in the winter is another most valuable root, the turnip, the introduction of 

 which into our system of agriculture has added millions to our national 

 revenue ; and they have often to lament the loss and distress occasioned 

 by a failure in this crop, of which these minor animals are the cause. On 

 its first coming up, as soon as the cotyledon leaves are unfolded, a whole 

 host of little jumping beetles, composed chiefly of Haltica Nemorum, 

 called by farmers thejfj/ 5 and blackjack, but assisted also by other species, 



1 The larvae above noticed were probably those of Psila Rosa Meigen (Psilomyia 

 Rosce Macquart), which Kollar (p. 161.) describes as attacking, carrots, residing 

 chiefly in the main root near the end. 



2 Kollar on Ins. inj. to Gardeners, &c. 155. 



3 Illiger, Mag. i. 256. 



* Passerini, quoted in Rev. Zool 1841. p. 354. 



5 The farmers would do well to change the name of this insect from turnip-Jit/ to 

 turnip-flea, since, from its diminutive size and activity in leaping, the latter name is 

 much the most proper. The term, the fly, might with propriety be restricted to the 

 Hop-aphis, and other species of the same genus ; and this is the more desirable, be- 

 cause the hop is also subject to the attack of a Haltica, which the hop planters are 

 judiciously beginning to distinguish by the name of the u flea." 



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