52 TRANSFORMATION OF INSECTS. 



during the night : and if the leaves are examined every morning, and 

 the slugs which are found destroyed, the piece of ground so treated 

 will soon be freed from them. Pea-haulm being very sweet when in 

 a state of incipient decay, forms a powerful attraction to slugs ; and if 

 handfuls of it are distributed over a piece of ground in the same man- 

 ner as the cabbage-leaves, the little heaps of haulm may be examined 

 every morning, and the slugs shaken from them and then destroyed by 

 watering with lime-water. Thin slices of turnip or potato placed 

 under inverted empty flower -pots form an excellent attraction, as do 

 the dead bodies of slugs themselves, some parts or the whole of which 

 are greedily devoured by the living animals. Where slugs are very 

 abundant in a soil not covered with plants so large as to shelter them, 

 as for example with rising seedlings, the slugs may be destroyed by 

 watering the soil thoroughly with lime-water, or tobacco -water, late 

 in the evening or early in the morning. Abundance of water should 

 be applied, in order that it may sink into the soil, which the slugs 

 penetrate a foot or more in depth, according to its state of pulveriza- 

 tion. Quicklime has been laid round plants to protect them from 

 snails and slugs ; but it soon becomes mild and of no use as a protec- 

 tion. Coal-ashes, sawdust, and barley chaff annoy slugs by sticking 

 to their foot, but they will not be deterred by this annoyance so 

 effectually as to starve for want of food. Soot is also a great annoy- 

 ance to slugs ; but to keep them from a plant, it requires to be fre- 

 quently and liberally renewed. Thorough drainage trenching and 

 frequently dusting the surface of infected ground, with caustic lime, 

 hot burnt earth, or ashes, will break up their haunts and exterminate 

 them, and such radical measures are the cheapest in the end. 



Insects, considered with reference to Horticulture. 



The number of species of insects in the world greatly exceeds that 

 of all other animals and plants put together, and the power which some 

 insects have of multiplying themselves, such as the plant lice for 

 example, is almost incredible. As by far the greater number of 

 insects live on plants, some on several species, and others on only one, 

 the importance of some knowledge of the natural history of insects to 

 the gardener is sufficiently obvious. 



Transformation of Insects. The greater number of insects properly 

 so called, with the exception of some without wings, change their form 

 several times during their life in so striking a manner, that a person 

 unacquainted with entomology would be inclined to consider one and 

 the same insect, in different periods of its existence, as entirely different 

 animals. 



Insects, in general, are produced from eggs ; a few species alone, in 

 which the eggs are developed in the body of the mother, are vivi- 

 parous ; for example, the aphis. Shortly after pairing, the female 

 lays her eggs, which are often stuck on, and covered with a sort of 

 glue, to preserve them from the weather, in the place best adapted to 

 their development, and which offers the proper food to the forthcoming 



