12 INTRODUCTION. 



|>ersons. If we would therefore endeavour successfully to 

 combat tin- latter, it c:iu only he (loue by tin- acquisition of 

 a knowledge of tlirir lial)its, in every state of tlieir existence; 

 and, in this point of view, the study of Entomology heroines 

 of the highest importance. Let us take, for instance, tin- 

 case of the turnip-flea beetle (or turnip fly, as it is often 

 called Halticanemorum), and we find that all the numerous 

 investigations of the Don- 

 caster Agricultural Associa- 

 tion have proved next to 

 useless, because the natural 

 history of the insect itself 

 was not ascertained. In like 

 manner it must be equally 



Turnip-flea Beetle evident, that tile (lili'llsioil of 



correct knowledge, and more 



especially inquiries into the chemical properties of man\ 

 insects, hitherto considered useless, might be the means of 

 adding considerably to the list of benefits conferred by 

 insects on man. 



Amongst the Crustaceous Annulosa many species of crabs, 

 lobsters, prawns, and shrimps are employed to a very great 

 extent as articles of food; and even amongst the winged or 

 true insects various species are found similarly serviceable. 



In the deserts of Africa and Asia, where the locusts ac- 

 quire a large size, those insects are employed, when dried 

 and preserved, as food. I have tasted locusts thus prepared. 

 and found them not unpalatable ; but they arc said to pos- 

 sess very little nutritious quality, and to produce disease 

 when too much is eaten. The larvae or grubs of many large 

 beetles are also devoured by the negroes of India and Ame- 

 rica: and even the luxurious Romans were exceedingly fond 

 of a large fleshy grub which they called (\sus, and which is 

 supposed to have been either the larva of the (mat-moth 



