418 



JOURNAL OF HOETICULTUEE AND COTTAGE GAKDENEE. 



[ November SO, 1871. 



recruited by it. The form in which he prefers to apply the salt 

 is in that of ashes of plants which contain a large per-centage 

 of it, such as Potato stems, Beans, &c., which contain as much 

 as five per cent. In the autumn of 1869 he dug round the 

 stems of half the trees in an old orchard, which had not borne 

 fruit for five or sis years, to the depth of 5 inches, and filled 

 up the space with about half a bushel of fresh ashes. In the 

 following spring and summer a dividing line might have been 

 drawn between the two sections of the orchard, the trees which 

 had been treated with ashes being forward and full in both leaf 

 and blossom, and subsequently presenting a still more marked 

 contrast as the autumn came on, and they were loaded with 

 Apples, while the other trees remained barren. Exceedingly 

 favourable results were also obtained when aged Peach and 

 Plum trees were treated in a similar manner. Crude potash 

 may also be used, but care must be taken that it is snffieiently 

 diluted before it is applied. — American FldlosopMcal Society, 

 Philadelphia. 



SOME PREDATORY INSECTS OF OUR 

 GARDENS.— No. 22. 



I HAVE already called attention, in one of my papers, to the 

 fact that amongst the few caterpillars to be found feeding late 

 in the autumn, that of the Large Garden White (Pieris Brassica;), 

 is notable. Indeed, I have seen some of these so small towards 

 the end of October, as to favour the supposition that they occa- 

 sionally hybernate. Most of them certainly enter the pupa 

 state before winter, and passing a garden the other day where 

 many of these caterpillars had been feeding up, I saw a num- 

 ber already in the pupa state, and others about to change. I 

 notice this comparatively trivial circumstance only to show that 

 naturalists are constantly exposed to error through coming to 

 hasty conclusions from imperfect observations. Upon a paling 

 a short distance from the spot where the bulk of them bad fed 

 up, a number of larvaj were scattered about, in various positions, 

 each one the prey of the larvte of the parasitic fly, which is the 

 peculiar foe of this species. There were very few, indeed, 

 which had escaped and become pupa3. Now, the first im- 

 pression of an observer would be this — " How extensively, in 

 this instance, has the species been attacked by its parasitic 

 enemy?" Yet further investigation proved that these were 

 merely the stragglers. Plenty of healthy pupaa were to be found 

 nearer the food plants ; and though the fly had, possibly, made 

 an attack upon a rather larger proportion of the caterpillars 

 than usual, there were not so many sufferers as might be 

 supposed. The caterpillar of Pieris Brassicaj, when thus 

 afiected, is smitten with a desire to wander; there is something 

 wrong in its interior, and it cannot understand it ; so that when 

 it has ceaped to eat it travels away from its food, making 

 abortive attempts at last to undergo its transformation at soma 

 distant spot, and there it dies. I find on inquiry amongst my 

 friends, that though very few of the spring brood of these cater- 

 pillars were to be seen, the autumn brood has been numerous 

 in some districts in the south of England. 



The history of the largest British Moth is so singular and 

 interesting that it ought not to be passed over, though it would be 

 a question for consideration whether it really does commit any 

 ravages of importance. Yet as, whenever it is seen, either as 

 moth or caterpillar, it is regarded by the uneducated (and 

 sometimes by the educated) gardener with dislike, or even 

 with dread, it has some claim to be noticed. The Death's 

 Head Hawk Moth (Acherontia Atropos) appears on the wing 

 in small numbers, in October and November, at a time when 

 insect life is almost stagnating. Still the majority of the in- 

 dividuals come abroad as images in the summer, and this for 

 some considerable period rendered the life history of the 

 Death's Head rather a puzzle to us. However, thanks chiefly 

 to the exertions of Mr. Newman, its economy has been eluci- 

 dated, and proves to be rather peculiar in some of its details. 

 The autumnal specimens of this Moth are mostly females, and 

 though a few may live on through the winter, most of them 

 die without making any provision for the continuance of the 

 species. Those which continue in the pupa state until the 

 year following emerge as moths in June and July, and deposit 

 eggs in the usual way. There is only one general brood of the 

 caterpillar of the Death's Head, and this occurs during July 

 and August. 



The Eev. J. G. Wood has given an amusing account of the 

 consternation which pervaded a group of villagers just return- 

 ing from church, when one of these Moths was discovered 

 resting on the footpath. All drew back in amaze and fear, ' 



until a blacksmith, the sturdiest individual of the party, stepped 

 forward, and with a sudden and dexterous spring brought his 

 heavy heel down upon the luckless insect, and people breathed 

 freely. Authors say that it is regarded with dislike on account 

 of the shrill cry it makes, and the skull-like markings on its 

 thorax, but in this case it does not seem to have been heard or 

 closely scrutinised. Probably it shares the indiscriminate dis- 

 like with which too many people regard insects of any sort, the 

 feeling being intensified in this instance by the size of the 

 moth. The caterpillar, as is abundantly proved by the com- 

 munications of entomologists and others to our journals during 

 the last few years, is called in many districts a " locust," or 

 "lokus," a singular designation, and in every way inappro- 

 priate. Though occurring in Potato fields, and on patches of 

 Potatoes in gardens (and in some seasons rather plentifully iE 

 certain districts, especially in the midland counties), I am not 

 inclined to believe that it does any notable amount of injury 

 to this important vegetable. For instance, both in 1865 and 

 1869 there were many records of its occurrence, and yet there 

 were no proofs that the Potato crop was diminished thereby. 

 Certainly from the large size of this caterpillar, and the time it 

 occupies in growing to maturity — about two months, I believe — 

 a single caterpillar would consume a considerable quantity of 

 leaves during its career, but I have yet to learn that in the 

 particular season of the year when it is about, much harm, or 

 any, in fact, is done to the Potato plants by the removal of a 

 portion of their leaves, especially those near the ground, a-od 

 which are already beginning to undergo decomposition. F or 

 these, it is said, the Death's Head caterpillar has in several in- 

 stances shown a partiality. It is, at least, well ascertained 

 that though this huge creature conceals itself sometimes during 

 the day beneath the surface of the earth, it does not gnaw the 

 tubers of the plant. 



The caterpillar of which we are speaking, though most fre- 

 quently discovered on the Potato, occasionally shows itself on 

 allied plants. The Jasmine is established as one of its food 

 plants, and also the Privet and the Thorn Apple, and it is- 

 found now and then on other species. As Eennie observes in 

 his remarks on the species, since it appears to be decidedly 

 indigenous, it no doubt fed upon the native species of So- 

 lanum and different Apocyuaj before the introduction of the 

 foreign species, the Potato and Jasmine, to which it now shows 

 a preference. On the Continent, the Death's Head caterpillar 

 occurs on fruit trees, such as the Mulberry and Pear. It is 

 evident from the habits of the species, that were it necessary 

 to keep it under, an examination of the plants by night with a 

 lantern would be likely to be of more utility than searching for 

 it in the daytime. Nor would it be impossible that this insect 

 should so increase in numbers as to be harmful, but this cir- 

 cumstance is highly unfavourable to it — at the period when 

 the Potatoes are dug up principally, it has gone into the pupa 

 state. Many must be killed by the spade or fork, and others 

 which are tossed on one side with the clods are exposed to the 

 weather, and as it is not very hardy while in the pupa con- 

 dition, probably most of the latter also perish. No doubt it is 

 a very wise provision for the partial preservation of these pupse- 

 from destruction, that the caterpillars when they have reached 

 their maturity descend some depth below the surface, and 

 thus are not only less likely to be unearthed by man or 

 animals, but they also secure for themselves a measure of immu- 

 nity from too much moisture and hard frost. 



The caterpillar of the Death's Head Moth, like the rest of 

 the Sphingine, is furnished with a horn above the tail, which in 

 this instance is recurved in a way peculiar to the species. If 

 it serves any purpose beyond that of ornamentation, it has not 

 been as yet discovered. There are two varieties of this cater- 

 pillar, which differ from each other not only in colour but also 

 in the character of the markings. The moths, however, pro- 

 duced from the typical form and the seemingly abnormal are 

 exactly alike. If annoyed it attempts to drive off its enemy by 

 uttering a peculiar sound, which has been compared to the 

 snapping of electric sparks. There is not, though, anything of 

 an electrical nature about the caterpillar; and though its powers 

 of biting must be proportionate to the size of the jaws, I find 

 no record of any instance of an individual having attempted to 

 defend itself in that way when handled by an investigating 

 biped. But, as I have repeatedly observed, some of the larger 

 caterpillars are by far the most pacific, while such as those of 

 the Buff-tip and Dagger Moths will repeatedly attempt to grip 

 the finger if it is presented to them. 



The moth is itself a predatory insect in onr gardens, if not of 

 our gardens, which it visits at the dusk of evening, seeking 



