Insects 



(443) 



Inula 



stage that the ravages of insects are most to be 

 dreaded, although it is obvious that in combating 

 insects it is important to kill the perfect insects or 

 egg layers. In a work of this scope it is impossible 

 to deal with the various wonderful changes that 

 go to make up the life of an insect ; they would 

 need a series of volumes to themselves. It may, 

 however, be mentioned that frequently the larva is 

 quite unlike the insect to which it will ultimately 

 give rise, but that occasionally larva and perfect 

 insect differ little except in point of size. The 

 larvae of bees and wasps are commonly called grubs. 

 They show little trace of a head, such as is seen 

 in caterpillars. The pupa stage is the quiescent 

 one. It comes when the larva is fully fed and 

 mature, and passes the winter usually in the ground 

 enveloped in one of a variety of coverings. The 

 larvae of butterflies and moths are enclosed in a 

 horny shell, which prevents almost all power of 

 movement. In the case of the silkworm, the 

 covering is a cocoon of what is known MS silk. 



In some of the aphides, multiplication by egg 

 laying is supplemented by viviparous females 

 throwing off perfect young flies in great numbers. 

 The rapidity with which aphides increase is well 

 known to all gardeners. While it is the larval 

 stage that is the injurious one to plants in many 

 cases, the aphides are harmful in their matured 

 condition, for the flies suck the juices of plants. 

 Beetles generally are furnished with strong jaws 

 for biting, and they do much damage in this way. 



In one respect at least, that of flower pollination, 

 insects play a most important part in the world of 

 plants. Many flowers have so developed them- 

 selves as to favour the class of insects which can 

 assist their fertilisation, and the division of what 

 the botanist calls " irregular " flowers has been 

 developed in this way. Familiar instances are to 

 be found in Delphiniums, Sweet Peas, and Orchids. 



It must be confessed that, of the numerous 

 insects with which the horticulturist and agricul- 

 turist come into contact, by far the greater number 

 have to be reckoned as enemies. There are, how- 

 ever, some which do no harm, and others which 

 are real friends. The latter, by reason of their 

 being parasitic upon injurious insects, render good 

 service to man. Chief among them may be men- 

 tioned the larvaa of the Ladybirds and the Lace- 

 wing flies, which eat green aphides in thousands ; 

 also the Ichneumon flies. The gardener will do 

 well to make himself acquainted with the appear- 

 ance of these, and by every means in his power 

 steer clear of hurting them. Other natural enemies 

 of insects are birds, and, although some species of 

 birds have an item on the debit side of the account 

 for fruit stolen, still there is no doubt that they 

 materially help to keep down the numbers of 

 plant-feeding insects. Unless this were so, indeed, 

 nothing would be able to live against the hordes 

 of insects. 



Artificial methods of keeping down insects in- 

 clude the use of insecticides (which see), the 

 digging of the soil in the autumn so as to expose 

 the pupae to birds, and dressing with lime, gas 

 lime, and other substances noxious to insects. In 

 some cases the plan of removing and burning the 

 top inch of soil beneath Gooseberry and liasp- 

 berry plantations is to be recommended, as many 

 hundreds of pupae are removed with the soil. 



Insects, the class Insecta of the entomologist, 

 are divided into the following principal orders: 



Coleoptvra, or Beetles These have powerful 

 jaws fitted for biting. The larvae of the Click 



Beetle are the dreaded wireworrns. Some of the 

 ground beetles are friends, as they are insectivorous, 

 but at least one of them, Harpalus ruficornis, is 

 harmful, as it now preys upon Strawberries. 



Orthoptera. Cockroaches, Locusts, and Earwigs 

 are included here. Chiefly enemies. 



Neuroptera,. Friends and neutral. The Lace- 

 wing flies are valuable allies of the gardener. 



Hi/nienoptera. Friends and foes. Among the 

 former are the Ichneumons and Honey Bee, and 

 amongst the latter the Sawflies, Gallflies, and 

 Wasps. 



J.epidoptera. Enemies. The larvce are cater- 

 pillars. The Onion fly, Crane fly, and Winter 

 Moth belong here. 



i/Vs/> v > '/, "YV Vv^ ^Sfc-' 



INULA OLANDULOSA (see p. 444). 



Hemiptera, inrliuling Heteroptera and Homoptera. 

 Enemies. The Phylloxera, Scale, and Aphides 

 belong here. 



Mention will be made of the various important 

 genera of insects under their names, and those 

 of the plants they attack. 



INULA. 



Hardy herbaceous plants (ord. Compositae), some 

 of which have large, showy, yellow flowers, and 

 bold, handsome leaves. All are of easy culture 

 and vigorous habit, and will succeed where many 

 other subjects fail. They are thus very suitable 

 for the wild garden, and may with advantage 

 find a place on the higher slopes of the rock 

 garden, where they will serve as a screen for more 

 tender plants. Propagation, by division of the 

 roots in spring. Fairly large clumps may be easily 



Tngen&ovttia (see Ampliitlinlea). 



Ink Herri/ (see Ilex fflahra). 



Inoculation (see Jluddinf/ ami Pollination). 



