270 



INSECT TRANSFORMATIONS. 



considerable size, and, of course, when abundant, 

 must destroy a vast number of aphides. 



Traiisformations of the iHcly-biril (Coccini.Ila 2-punctata, l.inn.) 

 a, the eags. 6, the luiva. c, ihe pupa, d, tlie beetle, c, the 

 same flying. /, Cocchielia 20-piinctot(i, Linn., flying. 



The maggots of many species of a beautiful family 

 (Syrphidce, Leach) of twu-winged flies are also 

 voracious devourers of the aphides. These larvse are 

 of a tapering Ibrm, and they can contract or lengtben 

 their bodies to a consideiable 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 Cyclo[)s did lor 

 Ulysses and his companions, till he touches one, 

 which he immediately translixes with his trident 



