INDIRECT INJURIES CAUSED BY INSECTS. 147 



ingenious Mr. Paul of Starston in Norfolk (well known as 

 the inventor of a machine to entrap the turnip- beetle, which 

 may be applied by collectors with great advantage to general 

 purposes,) has also succeeded in tracing this insect from the 

 larva to the imago state. His larvae produced Elater obscurus 

 of Mr. Marsham, which however comes so near to E. Segetis 

 that it is doubtful whether it be more than a variety. The 

 other species, however, of the genus have similar larvae, many 

 of which probably contribute to the mischief. When told 

 that it lives in its first (or feeding) state not less than five 

 years, during the greatest part of which time it is supported 

 by devouring the roots of grain, though it will also attack and 

 often much injure turnips, potatoes, &c., you will not wonder 

 that its ravages should be so extensive, and that whole crops 

 should sometimes be cut oiF by it. As it abounds chiefly in 

 newly broken-up land, though the roots of the grasses supply 

 it with food, it probably does not do any great injury to our 

 meadows and pastures.^ 



Here also may be included the larva of the long-legged 

 gnat {Ti'pula oleracea), known in many parts by the name 

 of the grub, which is sometimes very prejudicial to the grass 



1 The wire-worm is particularly destructive for a few years in gardens re- 

 cently converted from pasture ground. In the Botanic Garden at Hull thus 

 circumstanced a great proportion of the annuals sown in 1813 were destroyed 

 by it. A very simple and effectual remedy in such cases was mentioned to me 

 by Sir Joseph Banks. He recommended that slices of potato stuck upon skewers 

 should be buried near the seeds sown, examined every day, and the wire-worms 

 which collect upon them in great numbers destroyed. 



This plan of decoying destructive animals from our crops by offering them 

 more tempting food is excellent, and deserves to be pursued in other instances. 

 It was very successfully employed in 1813 by J. M. Rodwell, Esq. of Barham 

 Hall near Ipswich, one of the most skilful and best-informed agriculturists in 

 the county of Suffolk, to preserve some of his wheat fields from the ravages of 

 a small grey slug, which threatened to demolish the plant. Having heard that 

 turnips had been used with success to entice the slugs from wheat, he caused a 

 sufficient quantity to dress eight acres to be got together ; and then, the tops 

 being divided and the apples sliced, he directed the pieces to be laid separately, 

 dressing two stetches with them and omitting two alternately, till the whole 

 field of eight acres was gone over. On the following morning he employed 

 two women to examine and free from the slugs, which they did into a measure, 

 the tops and slices ; and when cleared, they were laid upon those stetches that 

 had been omitted the day before. It was observed invariably, that in the stetches 

 dressed with the turnips no slugs were to be found upon the wheat or crawling 

 upon the land, though they abounded upon the turnips ; while on the undressed 

 stetches they were to be seen in great numbers both on the wheat and on the 



land. The quantity of slugs thus collected was near a bushel Mr. Rodwell 



is persuaded that by this plan he saved his wheat from essential injury. 



L 2 



