336 M. Vibert on the Cockchaffer. 



As active devouring grubs ... 14 months. 



As inactive and fasting grubs - - - 10 



Existence as grubs - - - 24 



Existence in a state of chrysalis - 8 



Existence as May bugs in the egg, 20 days ; under ) 

 ground, 20 days ; and above ground, 80 days, - J 



Total period of their existence, 56 months. 



So that the greater part of their existence being in the grub state, a war 

 of extermination should be carried on against them while in that state. 

 The female chooses dunghills, compost heaps, ground lately moved and 

 open to the sun and air, to deposit her eggs ; rejects shady woods, under- 

 woods, and strong clayey ground. The most shady parts of M. Vibert' s 

 garden escaped, when the more open were infested. He found them 

 equally numerous on a naked fallow as among crops ; that they eat any 

 vegetable substance, dead or alive, devouring the very hooks used in layer- 

 ing plants. Grass, herbs, shrubs, and trees are equally their prey, and, 

 what is most strange, they are equally fat and healthy where they have 

 nothing, as when in the midst of plenty ! M. Vibert has noticed three 

 other sorts of grubs, which he thinks belong to the beetle tribe, but is un- 

 certain which they are. The depredations of the perfect insect are upon 

 high rather than low growths ; but the damage done by them is not to be 

 compared with the damage they do in their grub state. In 1825 their ra- 

 vages began, but were not so much felt as in the following year, for in that 

 year whole acres of lucerne, strawberries, &c, were totally destroyed. 



As means of destruction, M. Vibert thinks the Roman lettuce a better 

 bait than the strawberry, which has been recommended ; and digging, with 

 a view to gathering them, should be done in damp weather, for, on the 

 weather becoming dry, the grubs descend below the reach of the spade. 



From M. Vibert's book it is evident that the " white worm," Turk, or 

 miller grub, which he describes, is the larva of the Scarabse^us melolontha. 

 The only other beetle which has similar habits is the Scarabae'us solstitialis, 

 or hoary beetle. The latter is the smaller of the two, and, in some seasons, 

 equally plentiful. [Mr. Swainson, it will be observed (p. 295.), thinks it may 

 be the rose beetle.] In England both these species are the principal food 

 of rooks, jackdaws, crows, and sparrows. Rooks easily find them when 

 near the surface by the smell, and dig them up with great dexterity. 



Premiums to those who catch them, and forming heaps of dung, or 

 stubble which has been trampled for some time by cattle, to attract the fe- 

 males in their breeding season, are the only means which are practicable to 

 destroy them. A compost of bog earth and rotten dung, frequently turned, 

 and to which poultry should have access, would be an excellent trap for 

 them ; but probably the best of all traps is a heap or ridge of the sittings 

 of tan, after it has been rotted in the hot-house. — J. M. 



We have had three large and fourteen small grubs collected : half of 

 them we laid down on a gravel walk, and watered with lime water, of the 

 strength used for destroying worms, without succeeding in killing them ; 

 the other half we buried in a pot of earth, and watered with lime water of 

 double the usual strength, that is, at the rate of two quarts of powdered 

 lime to two gallons of water, and found them at first apparently killed, 

 but, on examining the pot after an interval of three days, they appeared in 

 as great vigour as before the lime was applied. We then tried half of them 

 with tobacco water, and half of them with salt and water : both mixtures 

 killed them ; but salt and water, . of a sufficient strength for that purpose, 

 would destroy vegetation, and tobacco water would be much too expensive. 



