IX PESTS 177 



known by its shape, which is something like that of 

 a leech, being widest at the tail and tapering gradu- 

 ally to almost a point at the head. It is blind, and 

 resting on its hind parts sways about the head and 

 neck groping for aphides and when it finds one 

 holds it up in the air and devours it, leaving the 

 skin behind. I have often seen and pointed out 

 this larva to friends, that it may be recognised by 

 its shape and escape destruction, for in size and 

 colour — green with a light central stripe — it is much 

 like one of the common caterpillars ; but I would 

 not advise that too much reliance be placed on the 

 efforts of our blind ally, for aphides can only be 

 kept completely under by sharp eyes and fingers 

 industriously and constantly used. 



A very beautiful lace- wing fly (Ghrysopa, i.e., 

 golden-eyed) also lays its eggs on a strange bunch of 

 stalks among aphides, and the larvae when hatched 

 despatch them very quickly. 



It will be seen, however, that all these insects 

 naturally require the aphides to be present before 

 the female will lay the eggs which are to produce the 

 larvEe to destroy them. We want to exterminate 

 the aphis, and this is necessarily not the object of the 

 aphis-eaters, for in that case their food and occupa- 

 tion would be gone. 



It is said that the Government of China pays a 

 handsome salary to the court physician while the 

 emperor is well, stops his pay when he is ill, and 

 chops off his head when he dies. This extremely 

 sensible system might, with the omission of the last 

 clause, be applied with great advantage by farmers 

 and other residents in the country to ratcatchers and 

 other professional destroyers of vermin. Unfortu- 



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