152 INDIEECT INJURIES CAUSED BY INSECTS. 



however, as to 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 

 electricus), and another poly pod {Polydesmus complanatus), 

 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 Muscidce. 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 immersed in the root 

 in an oblique direction, and in many instances they had 

 eaten off the end of it.^ 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.^ 



America has made us no present more extensively bene- 

 ficial, compared with which the mines of Potosi are worthless, 

 than the potato. This invaluable root, which is now so 

 universally cultivated, is often, in this country, considerably 

 injured by the two insects first mentioned as attacking the 

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

 moth (^Acherontia 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 mttatu), 

 of the same genus with the blister-beetle^ ; and another 

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

 the crops at Yolterra in Tuscany.* In the island of Barbadoes 

 some hemipterous insect, supposed to be a Tettigonia, occa- 

 sionally attacks them. In 1734 and 1735 vast swarms de- 

 voured almost every vegetable production of that island, 

 particularly the potato, and thus occasioned such a failure of 



1 The larvas above noticed were probably those of Psila Rosa Meigen (Pstlo- 

 myia Rosa Maequart), which Kollar (p. 161.) describes as attacking carrots, 

 residing chiefly in the main root near the end. 



2 Kollar on Ins. inj, to Gardeners, &e. ] 55. 3 JUiger, Mag. i. 256. 

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



