NATURE AND CLASSIFICATION OF INSECTS. 



for want of food. Soot is also a great annoyance to slugs ; but to keep them 

 from a plant, it requires to be frequently and liberally renewed. " A stout, 

 coarse, horse-hair line, such as is used for hanging clothes out to dry, coiled 

 round the stems of wall-fruit trees, and stretched along the wall, will operate 

 as a protection to the fruit from both snails and slugs, in consequence of the 

 bristly surface presented to them, and which they shrink from encountering. 

 Care must of course be taken that they do not get under it." (Penny Cyc.^ 

 Limax.} No gardener ought to rest content with merely protecting his 

 plants or fruits from snails and slugs ; because while they are in the garden, 

 as they must live, if they are debarred from attacking one plant they will 

 only have recourse to another. Nothing short of extermination, therefore, 

 ought to satisfy him, and this he may accomplish by enticing the larger 

 slugs into empty pots, or under cabbage- leaves or haulm ; and by soaking 

 thoroughly with lime-water the soil which he supposes to contain young 

 slugs or eggs. 



SECT. III. Insects^ considered with reference to Horticulture. 



305. 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 exam- 

 ple, 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. The subject, indeed, is one of great extent ; nevertheless every 

 gardener may readily acquire, from books and observation, such a know- 

 ledge of it as will suffice for the purposes of his profession. We shall there- 

 fore lay before him the essence of that part of it which more especially 

 relates to the insects which infest British gardens. We shall notice in suc- 

 cession the general nature of insects, their different stages of life, their 

 nourishment, propagation, duration, their natural enemies, and, above all, 

 the means employed by art to mitigate the evils which they occasion, or to 

 destroy them. We shall take as our guide Kollar, from whose treatise we 

 have abridged great part of the article ; and the whole has been revised for 

 us by J. O. Westwood, Esq., Secretary to the Entomological Society. 



Subsect. 1. Of the Nature of Insects and their Classification. 



306. Insects are animals which have a body consisting of one or more divi- 

 sions, articulated feet, and a head conspicuously distinct from the body, on 

 which are placed two movable horns, called antennae. They breathe through 

 airholes, which are situated on the sides of the body ; the greater number have 

 wings in their perfect state, and only a proportionably small number are 

 entirely without them. With the exception of certain groups, all perfect 

 insects have six feet, and their bodies are divided into a head, thorax, and 

 abdomen, by notches or incisions ; hence the name insect, derived from the 

 Latin word insecare, to cut or notch. Before they attain their perfect state 

 they are subject to various transformations, which are called metamorphoses. 

 For the sake of perspicuity the very numerous class of insects, the most 

 extensive in the whole animal kingdom, has been divided into two principal 

 divisions the winged, and the wingless. 



307. Winged insects are divided into the following orders : 



