INSECTS COLEOPTERA DIAGRAM 6. 117 



enemy ; but as it hides under ground, it is always difficult to get at 

 it. The best plan is to collect v^ry carefully all the cockchafers 

 which are found turned up by the plough ; but it must be remarked 

 that this plan is only available when the cockchafers are still near the 

 surface, in spring, or the beginning of autumn. If we wish to 

 destroy them in quantity, we must do the work at the exact depth 

 where the grubs are. If they are only two or three inches from 

 the surface, as sometimes happens, deep digging would turn up 

 very few ; but if they are far from it, a superficial examination is 

 altogether useless. But it is easy to ascertain first with a spade 

 at what depth the grubs are, and consequently at what depth it is 

 necessary to work. 



In the perfect state there is only one way of destroying the 

 cockchafers, namely, to collect as many as possible, for which the 

 local authorities ought to pay as much as they can. One remark 

 must, however, be made. The cockchafers that the collectors 

 should be paid for, ought to be all alive, or else it is useless to 

 collect them ; and they ought to be paid for very dear during the 

 first few days of their appearance, and the price should be lowered 

 afterwards. The reason is that during the first few days they 

 have not yet deposited their eggs, and are consequently of great 

 importance ; whereas it is not much use to collect cockchafers at 

 the end of the season, which have already laid 50 or 60 eggs in the 

 ground, which will produce as many grubs in succeeding years ; at 

 this time it is useless to continue the pursuit of cockchafers, and it 

 is wasting public money to pay for them. 



The cockchafers thus collected form when mixed with earth a 

 good manure. The best way of killing them is to plunge the bags 

 in which they are brought into boiling water. 



Cantharides. The name of cantharides is often applied to all 

 bright green beetles. But the true Cantharis is a rarity in the 

 South of England, and is too scarce to be of any commercial 

 importance. It is met with in May and June on jasmines, 

 ash-trees, and lilacs. There is a great trade in cantharides for 

 medical purposes. They are largely collected on the Continent, 



