MAGGOTS. 419 



of the mail- coach man whether he had heard this stoiy ; 

 and he said the fact was well known."* The year in 

 which this remarkable circumstance occurred is not men- 

 tioned. 



The importance of the insects just mentioned, in re- 

 moving with great rapidity what might otherwise prove 

 nuisances of considerable magnitude, naturally leads us to 

 notice another sort of larva, no less useful in diminishing 

 the numbers of the plant-lice (^Aplddes) which do so much 

 damage to cultivated vegetables. We do this also the 

 more readily, that these very insects, which are so benefi- 

 cial to the husbandman and the gardener, are often erro- 

 neously accused of being themselves the cause of the mis- 

 chief. A correspondent of the ' Natural History Magazine,' 

 for example, says, " the lady-bird is remarkably abundant 

 this season. The shrimp (larva) of this insect destroys 

 both turnips and peas in many parts of England."t The 

 truth is, however, that all the species of lady-birds ( Cocci- 

 nelli(lo2, Latr.), both in the larva and the perfect state, feed 

 exclusively on aphides, and never touch vegetable sub- 

 stances. The eggs are usually placed in a group of twenty 

 or more upon a leaf where aphides abound ; and when the 

 young are hatched they find themselves in the midst of 

 their prey. There are a considerable number of species of 

 this family (Mr. Stephens enumerates fifty) : but the most 

 common, perhaps, is the seven-spotted lady-bird (Coccinella 

 ssptempunctata), whose larva is of considerable size, and, of 

 course, when abundant, must destroy a vast number of 

 aphides. 



The maggots of many species of a beautiful family (Syr- 

 phidcB, Leach) of two-winged flies are also voracious devour- 

 ers of the aphides. These larvae are of a tapering form, 

 and they can contract or lengthen their bodies to a consi- 

 derable extent ; while they have a retractile instrument, 

 armed with three prongs like a trident, with which they 

 transfix their helpless and hapless victims. " When dis- 

 posed to feed," says Kirby, " he fixes himself by his tail. 



* lutr. vol. i. p. 140, and 7iote. f Mag. of Nat. Hist. vol. i. p. 191. 



