THE MELOLONTIIIDAl. 



273 



then the cold of the autumn may prevent the perfect insect from 

 leaving its cell — so that it does not fly until the spring of the third 

 year. The larvae are shaped like those of the Scarabaidce gene- 

 rally, and they are remarkable for their strong mandibles, which 

 are furnished with a diamond-shaped tooth that enables them to 

 cut across rootlets very easily. 



It would appear that the larvae of the May bugs, found as 

 they are over the whole of Europe, were not formerly such pests 

 to farmers. They were certainly not so common in the olden 

 time, but they appear to have increased their numbers with the 

 spread of agriculture. Farming operations favour these creatures, 

 for they cannot live in undisturbed ground ; they cannot move 

 about in solid earth or in old rocks, but they can do so in alluvial 

 soils, or in those which the process of tillage renders light and 

 suitable for vegetation ; and, formerly, the acreage of cultivated 

 ground w^iere the May bug larvae can live was, of course, much less 

 than it is now, and consequently the beetles were not so common. 

 The larvae must be dug up to be destroyed, and this is a very 

 awkward operation whilst ploughing and spade husbandry are going 

 on. It is much easier to collect the beetles themselves, and if they 

 were well hunted down everywhere simultaneously, there w'ould 

 be no doubt about a rapid diminution in the numbers of the larvs ; 

 but, unfortunately, all the efforts of men who are sufficiently 

 enlightened to advise the farmer rarely meet with success. Thirty 

 years ago, a Prefect in the Department De la Sarthe — M. de 

 Romieu — took great pains, and persevered in urging upon agri- 

 culturists to destroy the real originators of the mischief they 

 suffered from ; and of late years M. Riset has been studying the 

 amount of mischief these creatures really commit. He found that 

 in two arrondissements in the Department of Seine Inferieure, 

 360,000 lbs. weight of cockchafer grubs were found ; and as a 

 grub only weighs about thirty-one grains, there must have been 

 81,290,322 of them. 



With this calculation before us, which refers only to two small 

 districts, it is not difficult to understand the enormous amount of 

 injury that is done to agriculture by these grubs. Very fortunately 

 rooks, jays, magpies, crows, and other birds, eat immense quan^ 

 titles of them, and this fact alone ought to make us careful of 



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