270 



INSECT TRANSFORMATIONS. 



considerable size, and, of course, when abundant, 

 must destroy a vast number of aphides. 



Transformations of the lady-bird (Coccindla 2-punctata, Linn.) 

 , the eggs. 6, the larva, c, the pupa, d, the beetle, e, th 

 same flying, y, Coccinella 20-punctata, Linn., flying. 



The maggots of many species of a beautiful farm'lj 

 (Syrphidce, LEACH) of two- winged flies are also 

 voracious devourers of the aphides. These larvae are 

 of a tapering form, and they can contract or lengthen 

 their bodies to a considerable extent; while they have 

 a retractile instrument, armed with three prongs like 

 a trident, with which they transfix their helpless and 

 hapless victims. ' When disposed to feed,' says 

 Kirby, * he fixes himself by his tail, and being blind, 

 gropes about on every side, as the Cyclops did for 

 Ulysses and his companions, till he touches one, 

 which he immediately transfixes with his trident 



