UTILITY OF INSECTS. 269 



surgeon, he presented a sight loathsome in the ex- 

 treme; white maggots of enormous size were crawl- 

 ing in and upon his body, which they had most 

 shockingly mangled, and the removing of the exter- 

 nal ones served only to render the sight more horrid.' 

 Kirby adds, c in passing through this parish last 

 spring, I inquired of the male-coachman whether he 

 had heard this story; and he said the fact was well 

 known. '* The year in which this remarkable cir- 

 cumstance occurred is not mentioned. 



The importance of the insects just mentioned, in 

 removing 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 (Jlphides) 

 which do so much damage to cultivated vegetables. 

 We do this also the more readily, that these very 

 insects, which are so beneficial to the husbandman 

 and the gardener, are often erroneously accused of 

 being themselves the cause of the mischief. A corre- 

 spondent of the Natural History Magazine, for exam- 

 ple, 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, 'f 

 The truth is, however, that all the species of lady- 

 birds (Coccinellidce, LATH.), both in the larva and the 

 perfect state, feed exclusively on aphides, and never 

 touch vegetable substances. 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 septempunctata) , whose larva is of 



* Intr. i, 140, and note. t Mag. of Nat. Hist, i, 191. 



rot, vi - 23* 



