INTRODUCTION. 



Mosquito (the figures show the mosquito 

 'Anopheles in positions of rest, much enlarg- 

 ed) who, light as any sylph on the wing, 

 approaches with that delicate swing and 

 pinging buzz which chases away sleep and 

 sets every muscle and sense on the alert ? 

 Have we not seen those marvellous 

 and inexplicable invasions of the great 

 Migratory Locust, the locust of the 

 Egyptian Plagues, gradually spreading 

 themselves through the length and 

 breadth of the Continent, from their 

 homes in the sandy desert fastnesses of 

 Rajputana, Sind and Baluchistan ? 

 Are not the periodical eruptions of this 

 pest still a source of mystery and a sub- 

 ject of disagreement amongst scientists 

 who have endeavoured to study the 

 habits of this insect and have wished to 

 give chapter and verse to account for 

 its migrations from its desert homes? 

 Have we not, some of us, seen or read in 

 our newspapers of heavy mail trains 

 brought to a standstill owing to great 

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