276 BENEFICIAL INSECTS. 



The larva that hatches is an active spiny insect, with long- 



Fig. 337. 

 Larva of Chrysopa, just hatched, on the egg, {^Magnified.) 



sharp jaws ; it runs about the plant seeking for aphis and when 

 it finds one, the jaws are inserted and the 

 juice sucked out till only the shell is left. 

 In some species the larva covers itself in the 

 cast skins of its victims and goes about with 

 a thick mass of them on its back. This 

 larva destroys a large number of the aphis 

 before it pupates ; the pupa is found in a 

 small white cocoon or in a fold of the leaf 

 under a thin covering. These insects are very 

 numerous in the plains, thoug-h they commonly 

 escape notice. A bad attack of aphis brings 

 them in numbers and the flies are attracted to 



Fig, 338. 



jEgg of Sgrphus 



Fig laid on leaf. 



(Natural size 



and much magnifed.) 



light. 



^flTfr 



Fig. 389. 

 Qrub of Syrphus Fly. {Magnified five times.) 



