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“V. Some Observations on the Economy of an Insect destructive to Turnips. By Wit11am 
Yarre.L, Esq., V.P.Z.S8., F.L.S., &c. 
Communicated November 24, 1835. 
ALTHOUGH the days are for ever gone by when any one seen feeding a caterpillar, 
digging for a grub, or with expanded net endeavouring to capture an insect on the 
wing, would be considered as intellectually below the standard of his fellow men, still 
there are not wanting those who require to be convinced of the utility of entomological 
investigations ; and by no better mode can the entomologist prove the value of the 
science he cultivates than by a practical application of the knowledge he acquires of 
the properties and economy of insects, to secure the advantages to be obtained from 
some, and to prevent the injuries inflicted by others. 
To the agriculturist in particular the, labours of the entomologist are calculated to be 
of the deepest interest. The injury that has recently been done to the sugar cane, to 
the amount of one third of the produce of the crop, by the rapid and alarming progress 
of a small but most destructive insect in the island of Granada, its ravages now ex- 
tended over two thirds of the island, and its appearance in the neighbouring islands, 
may be quoted as an instance abroad ; while the serious losses sustained by the growers 
of turnips in our own country, particularly during the last summer, bring the various 
sufferers to the entomologist for his assistance, perfectly aware that a knowledge of the 
life of the insect through all its various states and changes is the first important step 
towards the adoption of some effectual method of preventing its future depredations. 
The destruction of a portion of the turnip crop in this country, usually effected by the 
larve of two small insects, the Haltica nemorum and Halt. concinna of authors, has long 
afforded a subject for investigation ; and the reader who is interested may consult with 
advantage the ‘ Report of the Committee of the Doncaster Agricultural Association’! 
on this subject. I may here add that there is now a better prospect of checking the 
ravages committed by the young of these little beetles, the larva and pupa having lately 
been accurately ascertained, and specimens sent to the Entomological Society of Lon- 
don, with a communication, by Mr. Lekeux. 
But the destroyer of a very large proportion of the turnip crop, on the light and 
chalky soils of this country, during the last dry summer, is an insect of a different 
kind, and one that happily does not make its appearance in great numbers except at 
wide intervals, and during those seasons that are remarkable for the almost total absence 
of rain. 
The first public notice I am acquainted with on the subject of this particular insect, 
* Ridgway and Sons, Piccadilly, 1834. 
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