510 



JOUBNAL OF HORTICULTURE AND COTTAGE GARDENER. 



[ December 9, 1875. 



expenditure on nselesa bloom to improving and invigorating 

 the growing parts, and acting in that way, if it does, must 

 contribate immensely to the after-support of the fruit and 

 vitality of the tree itself. 



The next stage to which I will allude is the commencing of 

 the stoning process, and the advantage is here in favour of the 

 moderately vigorous tree and the weak, for the vigorous tree 

 oasts its fruit to an alarming extent. If the fruit be cut we 

 find a kernel of watery matter, or the dried empty skin of the 

 seed, or hollow cavity, the footstalk of the fruit dried up, and 

 the fruit itself shrivelling. There is a cause for this no doubt, 

 yet what that may be I could never ascertain. It is clearly 

 not an effect of treatment nor of overcropping, but, contrary- 

 wise, luxuriance of growth. Can it be that the growth being 

 gross the ascending sap is imperfectly elaborated in the fruit, 

 and the descending juice or cambium is diminished in propor- 

 tion from the great loss consequent on the excessive exhalation 

 from the leaves and fruit surfaces of gross trees as compared 

 with the moderately vigorous? This I think is the case, for, 

 first, the fruit invariably shrinks ; and second, if a ligature be 

 placed on the branch or shoot bearing fruit below the fruit so 

 tight as to compress the sap vessels, the fruit seldom drops. 

 I contend, therefore, that as the trees at this stage grow but 

 slowly, that the process is being undergone in respect of the 

 fruit similar to that occurring later on in respect of the wood 

 — viz., its ripening. The ascending sap being excessive, growth 

 and unfruitfulness ensue ; but the ascending sap being mode- 

 rate, the descending is greater correspondingly from the lesser 

 exhalation taking place by the leaves and fruit, and the parts 

 are more fruitful. The casting of the fruit at this stage is 

 analogous to that described in the " Science and Practice of 

 Gardening," page 330, summed up in the following terms : — 

 " A similar defective fertility occurs if the female parent in 

 animals is over-stimulated and fat." 



The third stage is the stoning one, and this is certainly, in 

 respect of the fruit, similar to the ripening of the wood. The 

 seed is with the completion of the stone perfect, as with the 

 ripening of the wood the buds are rendered fertile or otherwise 

 abortive. The two last stages are dependant upon the condi- 

 tion of the parent. It is not a result of imperfect impregna- 

 tion, but of grossness of growth, or its opposite, weakness, 

 and resultant from overcropping. If the growth of the trees 

 be gross, and much wood is made during the stoning, few 

 fruit will pass it safely ; and in the case of a weak tree, from 

 the ill supply of nutriment, the fruit, if at all abundant, does 

 not stone, a number of fruit dropping, but not to such an 

 extent as in the gross subject ; whUst the moderately vigorous 

 tree, with stout short-jointed wood, not overcropped, and its 

 growth stationary or nearly so during the stoning period, 

 passes the stage with the loss of few, if any, fruit, and what do 

 fall are the small and iiaperfeot. 



The importance, then, of the ripening of the wood or the 

 deposition of cambium is essential to the fruit passing the first 

 stage, also the second and third, and points to our avoiding 

 the extreme of moisture and over-stimulating food during 

 those periods or those immediately preceding, " inasmuch as 

 an abundant supply of these increases excessively the develop- 

 ment of the succulent parts of the fruit, and yet the vessels 

 from this to the seed often wither and render it abortive." — 

 Science and Practice of Gardening, page 330.— G. Abbey. 



CHAPTERS ON INSECTS FOR GARDENERS. 



No. 4. 



Though it is but a word of three letters, I consider the word 

 " fly " to be one of the broadest words in the English language, 

 since it serves in its popular asceptation to cover such a mul- 

 titude of insects. Besides flies proper we have no end of flies 

 improper rejoicing in this appellation. Many species of the 

 Hjmenopterous order are flies with most folk ; so are the 

 dragon flies, the May flies, and other Neuroptera. The Hemi- 

 pterous aphis and sundry relatives rejoice in this epithet, and 

 so do the caddis flies. More than that, the name touches the 

 unlikely order of the beetles, for allaltica is a Turnip fly; and 

 day-flying species amongst the gaudy tribe of the Lepidoptera 

 are butterflies, or even simply flies. In fact it might not be 

 diflficult to establish the theory that originally English folks 

 called every insect that could fly a fly ; though, on the other 

 hand, there is no evidence that people called insects which did 

 not fly a " creep " or a " crawl," yet it would have been quite 

 as appropriately vague. Flies, however, to speak scientifically, 

 constitute the important order of the Diptera or Two-winged 



insects, placed by some writers on entomology at one end of 

 the insect class, and by some writers at the other end. As we 

 work from the lower to the higher the consideration of it 

 comes here. To most persons the name at once suggests 

 annoyance or loss, and visions come up of the house fly, the 

 bluebottle, the gnat, the mosquito, the gadfly, and less-known 

 species of a like evil repute, while the horticulturist has his 

 special reasons for disliking the Diptera ; and yet these insects 

 render important services to mankind at large, and some ser- 

 vices worth mentioning to the flower, kitchen, and fruit garden. 

 Pre-eminently are the scavengers of the insect race represented 

 amongst the flies ; and their labours in decomposing and de- 

 vouring substances which would otherwise be noxious or at 

 least useless, were recognised long centuries ago by the men 

 who in old Greece and Italy groped eagerly and painfully after 

 the truths of natural science. 



So far as numbers are concerned flies take the lead amongst 

 insects, though in point of size many of the species occupy 

 only a low place. Flies have not inappropriately been termed 

 the pioneers of the insect host, for it has been observed that 

 on barren lands which have been brought under cultivation, 

 and where insect life was previously lacking, the first species 

 that present themselves are these two-winged insects. I dare- 

 say a look of disgust steals over the face of many a gardener 

 as he contemplates the " insects of the sunshine," about which 

 the poets have gone into rhapsodies, and most of which belong 

 to the Dipterous order, and wishes they would take their aiirial 

 excursions anywhere else but in his domains. Yet really I, for 

 my part, would venture on the assertion that on the whole we 

 have more reason to view the Diptera with friendliness than 

 with disfavour, though I know there are some who would 

 maintain the opposite. It is certain that of the multitude of 

 flies one sees about the garden or the conservatory the majority 

 are only intent upon imbibing the honey of flowers and have 

 no sinister designs, and a proportion of them are directly or 

 indirectly beneficial to us. Of course there remains yet a pro- 

 portion that are injurious either in the fly state, or, more 

 frequently, while in the larval or maggot condition. Mean- 

 while I would urge the reader to keep in mind these four facts, 

 which I put as curtly as possible lest he should say emphati- 

 cally in the words of a popular refrain, "Bother the flies!" 

 First, then, various larva) of flies do service as scavengers in 

 preparing decomposing matter for the enrichment of the 

 ground ; secondly, many flies as images and larvse prey upon 

 other insects, and also on other flies ; thirdly, the fertilisation 

 of flowers is frequently brought about by the passage of flies 

 from one blossom to another ; and fourthly, flies supply an 

 important element of food to numerous birds which would 

 otherwise attack vegetation. It is well known that when much 

 damage is done to the buds in spring the birds who have been 

 concerned in the matter have had difficulty in obtaining suffi- 

 cient insects for their requirements, and so they fall upon the 

 tender leaf buds. Of course I grant that sometimes the birds 

 open buds for the sake of the insects they contain. 



The particulars which need to be noted to enable us readily 

 to distinguish the bulk of true flies are brief and simple. The 

 two wings are clear and are never folded, while in place of the 

 hind wings found in other orders we have a pair of balancers 

 or poisers ending in a small knob. The mouth is best known 

 by its proboscis or sucker, rendered still more ellective in 

 some species by an accompanying array of lancets, represent- 

 ing what amongst the biters of the insect tribes we call the 

 mandibles and maxillfe. The pupa of a fly is always inactive, 

 nor does its shape give any clue to the insect enclosed. The 

 famihar maggot or larva is legless and most usually simple in 

 form, though a few species with aquatic habits are curiously 

 decorated with appendages having to do with the breathing or 

 swimming apparatus like that of the common gnat. The eyes 

 are large, sometimes seeming to absorb the whole of the head. 

 In the structure of the legs we notice that the tarsus (which 

 represents what we call the calf in the human subject) has 

 five joints, the feet being clawed and provided with flat hairy 

 pads, generally two in number, occasionally wanting. These 

 pads enable flies to perform those feats, so astonishing to the 

 eye, in the way of walking head downwards on substances 

 which offer no grip ; and even when the structure of the fly is 

 examined there is stOl some difficulty in comprehending " how 

 it's done." Flies, however, are not the only insects thus 

 skilled in gymnastics, though they have been spoken of as if 

 they were singularly clever in this mode of progression. 



The very small division of the flies called the Eprobosoidea 

 only require a few words, as they do not concern gardeners, 



