INSECT "BLIGHTS AND BLESSINGS." 



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full grown is half an inch long, its body thickest at the tail 

 end, gradually tapering towards the head, in which the mouth, 

 formed much like a hook, is found. Attaching itself firmly to 

 the midrib by means of its anal claspers, or "feet," the maggot 

 moves its attenuated body about, swaying from side to side, 

 much after the manner of a leech. I have frequently watched 

 the emergence of these larvae from the eggs scattered over the 

 leaf, and sometimes, even before it has become clear of the egg- 

 shell, its head has touched a Green Fly, which it immediately 

 seizes and sucks dry. The flavour is so acceptable to its palate 



Fig. 19. 



that for the rest of grub-life it feeds on nothing else. Its appetite 

 is astounding : I have watched one specimen hoist up into mid- 

 air (fig. 19) and suck dry over one hundred and twenty Green 

 Flies in one hour. I look upon this as a record meal, but the 

 number destroyed by one larva of Wasp Fly during its life of ten 

 to thirteen days is simply prodigious. At the end of this time 

 the maggot attaches its claspers to either a leaf or stem, where 

 it undergoes its change to the chrysalis (fig. 20), the form 

 and colour of which so much resemble a shoot that this 

 protective resemblance preserves it from attack by birds. In a 

 few days the matured Fly bursts forth from its shroud a living 



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