oJ 
 
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 Miscellaneous Publications, No. 37. 
 
 
 MINISTRY OF AGRICULTURE AND 
 , - FISHERIES, 
 
 BENEFICIAL INSECTS. 
 
 *'* .% i "'",*"** s" i s * 
 
 LONDON : 
 
 PRINTED UNDER THE AUTHORITY OF HIS MAJESTY'S 
 STATIONERY OFFICE. 
 
 And to be obtained at the Office of the 
 
 MINISTRY OF AGRICULTURE AND FISHERIES, 10, WHITEHALL 
 PLACE, LONDON, S.W.I. 
 
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 1922. 
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Miscellaneous Publications, No. 37. 
 
 MINISTRY OF AGRICULTURE AND 
 FISHERIES. 
 
 BENEFICIAL INSECTS 
 
 LONDON : 
 
 PRINTED UNDER THE AUTHORITY OF HIS MAJESTY'S 
 STATIONERY OFFICE. 
 
 And to be obtained at the Office of the 
 MINISTRY OF AGRICULTURE AND FISHERIES, 10, WHITEHALL 
 
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LIST OF CONTENTS. 
 
 PAGE. 
 
 Introductory - - 3 
 
 Ladybirds - 3 
 
 Plate I. - (facing) 4 
 
 Ichneumon Flies 5 
 
 Tachinid Flies - 7 
 
 Hover Flies 7 
 
 Lacewing Flies - - 8 
 
 Plate II. (f^ing) 8 
 
 Artificial encouragement of Beneficial Insects - - - 9 
 
 Technical Description of Plates - 11 
 
BENEFICIAL INSECTS. 
 
 
 
 $r*,ry 
 INTRODUCTORY. 
 
 In their relation to cultivated crops, insects may conveniently 
 be divided into three groups, viz. : 
 
 Pests those which are harmful, causing by their 
 depredations serious loss to the cultivator and a diminution 
 of the country's food supply; 
 
 Neutral or negligible those which do not directly 
 influence crop production ; 
 
 Beneficial those which by predaceous or parasitic 
 habits diminish and keep in check the numbers of the 
 Pests. 
 
 There is some overlapping between these three groups, but 
 it is generally possible to assign an insect to one or the other. 
 
 In considering beneficial insects from the cultivator's point 
 of view, it is only possible to deal with certain large groups, 
 various members of which attack and destroy the worst insect 
 pests to agriculture and horticulture. Of these groups, five are 
 outstanding as amongst the very best friends possessed by the 
 farmer, gardener and fruit-grower : they are Ladybirds, Lacewing 
 Flies, Hover Flies, Ichneumon Flies, and Tachinid Flies. Only*' 
 too frequently these insects are mistaken for foes and destroyed. 
 It is hoped that the brief descriptions of them and short outlines 
 of their life-histories herein given may help towards their wider 
 recognition. 
 
 In connection with all of them one point must first be 
 emphasised : Beneficial insects seldom, if ever, exterminate a 
 pest, or extermination of themselves would be likely to follow. 
 The most they do is so to check the pests (which would other- 
 wise breed in colossal numbers) that the damage suffered by 
 crops is reduced to an almost negligible amount. Their work 
 of destruction goes on unobtrusively, and only fails when some 
 influence favours the pest or acts adversely on the parasite, 
 allowing the former to survive in such overwhelming numbers 
 that an effective control no longer obtains. The cultivator 
 himself must then resort to artificial measures of pest destruc- 
 tion, but in doing so he must remember that he is often killing 
 both friend and foe alike. He must, therefore, having once 
 begun, be prepared to continue his spraying or other measures, 
 and himself carry out the work previously left to Nature. 
 
 LADYBIRDS. 
 
 Ladybirds are beetles which do untold good by feeding in 
 the adult and grub (larval) stages upon Aphides (Greenfly or 
 " Blight "). Some kinds also feed on Scale Insects, Suckers, or 
 other pests. 
 
 r (5)16948 Wt P 2120 R 7 10,000 4/22 
 
 M160927 
 
The adult Ladybird is well known and is usually respected 
 by everybody; but in the grub stage, being so very different 
 in appearance and somewhat repulsive to look at, it is by no 
 means so often recognised and frequently falls a prey to the 
 uninformed zeal of the gardener, who complains of Greenfly 
 while he busily destroys perhaps its greatest enemy the Lady- 
 bird grub. The appetite of these grubs is enormous and they 
 appear to feed almost continuously, 30 to 40 Aphides being 
 devoured with scarcely a pause. 
 
 Description and Life History. The Eggs (Plate L, Fig. 2) of 
 the Ladybird are conical in shape and yellow in colour, going 
 brown when about to hatch. They are placed by the adult 
 insect in small groups upon the stem or underside of the leaves 
 of a plant infested by Aphides. 
 
 The Grub (Plate I., Fig. 3) is a flattish, black, ugly creature 
 with a big head and six legs on the fore part of the body. In 
 some species it is marked with yellowish or reddish and white 
 markings. After hatching from the egg, it soon begins to hunt, 
 and on arriving at the first group of Aphides eats its way 
 steadily through them. It is very active, an indefatigable 
 hunter, and, on having killed out the prey on a particular plant 
 or branch, will pass rapidly to the next. It grows quickly, 
 changes its skin several times, and on becoming full-fed turns 
 to a pupa on the plant or anything adjoining. 
 
 The Pupa (Plate I., Fig. 4) is a pomewhat dried-up looking 
 object when first formed, light yellow, but afterwards darker 
 in colour. The shrivelled skin of the grub, out of which the 
 pupa has emerged, remains wrapped round the " tail." After 
 a few days, varying with the season, this pupa splits and the 
 adult Ladybird crawls forth, being at first soft and pale, but 
 hardening in a few hours and attaining the characteristic 
 coloration. 
 
 The Perfect Insect (Plate L, Fig. 1). The little round, red 
 beetles with black spots, known as Ladybirds, are familiar to 
 everyone. There are, however, many kinds, some red or yellow 
 with black spots, others black with red spots. In certain kinds 
 even the separate individuals vary in colour from black to red 
 according to which colour predominates. Nearly all, however, 
 have the characteristic shape and appearance, so that, apart 
 from colour, they may easily be recognised as undoubted 
 Ladybirds. 
 
 On emergence from the pupa, Ladybirds soon begin to feed 
 upon Aphides. The females, after pairing, lay eggs and the 
 life-cycle begins again. There are several broods throughout 
 the summer, the last one hybernating. spending the winter 
 asleep under bark of trees or in some cranny, when at times 
 considerable numbers collect together in one place. With the 
 warmth of spring they emerge from their hiding places and the 
 first eggs of the season are laid. 
 
ICHNEUMON FLIES.* 
 
 Under this popular designation may be included several 
 thousand allied species of insects, examples of which are shown 
 on Plate I., Figs. 6, 7, 8 and 9. They are not flies in the 
 zoological sense, but are all close relations of the bees and wasps, 
 albeit not necessarily like them in appearance. They range in 
 size from extremely minute insects, hardly visible to the naked 
 eye, up to as long or even longer than the Hornet, though less 
 heavily built. They have jaws, long antennae, and four wings, 
 which are always carried along the back and are small in propor- 
 tion to the creature with few ribs in the supporting framework. 
 In habit they are very active and energetic. Ichneumons probably 
 comprise (with the possible exception of adverse weather condi- 
 tions) the most potent of all the forces operating to keep in 
 check an overwhelming increase in other insects a misfortune 
 which always threatens. They do not achieve this by devouring 
 them outright as the Ladybird does, but are parasitic and lay 
 their eggs in or upon the insects they attack. The Ichneumon 
 grubs then feed upon the juices of their victims and come to 
 maturity in their stead. Practically all the other orders of 
 insects are laid under contribution. It would be quite impossible 
 to enter here fully into the immense activities of Ichneumon 
 Flies ; suffice it to say that most of the grubs and caterpillars 
 that destroy cultivated crops are known to be attacked. The 
 dried skins of Aphides containing the parasitic grub and forming 
 a covering for it, can always be found in considerable numbers. 
 In fact, practically all the more serious pests are destroyed by 
 Ichneumons. 
 
 Unlike the Ladybirds and Lace wings, of which the grubs 
 are too frequently destroyed in ignorance, the large group of 
 parasitic insects here called Ichneumon Flies need no special 
 plea for their preservation, for in the early stages they are out 
 of sight or not prominently noticeable, and as adults are active, 
 watchful and able to take care of themselves. 
 
 Description and Life History. The Eggs are deposited in or 
 upon (usually in) the bodies of other insects by means of a 
 special egg-laying apparatus. It is usually the egg, grub or 
 pupa stage which is attacked. 
 
 The Grub, with a few exceptions, is a whitish, legless maggot, 
 like its cousin the wasp-grub in appearance but differing in size 
 according to the species. In the case of the internal feeders, 
 it lives on the juices of its prey which it eventually destroys, 
 but not before it has itself become full-fed. In some cases, it 
 leaves its prey and spins a cocoon itself ; in others it waits until 
 its victim has spun a cocoon before killing it and then merely 
 
 * For the purposes of this publication the designation " Ichneumon 
 Flies " is made to cover the greater part of the Hymenoptera Parasitica 
 as well as the Ichneumonidce, viz., Braconidce, Proctotrypidce, Chcdcididce, 
 <fec. 
 
6 
 
 lies naked in that. A small minority of species feed on the- 
 outside of their prey, sucking the juices through the skin. 
 
 The grubs of the Ichneumon Flies being for the great part 
 internal feeders, are naturally very seldom seen; the case most 
 often observed, perhaps, is when a large number of small white 
 maggots are found emerging through the skin of a Cabbage 
 Butterfly caterpillar to spin a bunch of white or yellowish- 
 white cocoons (Plate I., Fig. la) on the leaf near-by, from each 
 of which will emerge in due course a small black Ichneumon 
 (Braconid) (Plate I., Fig. 7). 
 
 The Pupa is like the perfect insect to be, but covered with 
 a fine white skin on all its parts, the whole creature being white 
 until some days before emergence from this pupal covering, 
 when the colours it will eventually assume gradually appear, 
 starting with a darkening of the eyes. 
 
 The Perfect Insect. On the pupal skin splitting and being 
 worked off backwards like a glove, the perfect insect is disclosed 
 with all its parts free. At first it is soft and does not come 
 forth like a butterfly to dry, but remains some time within the 
 cocoon until all its parts have hardened, when it eats a way 
 out, and, having paired, the female begins to hunt for the prey 
 to which she is attached and in or upon which she lays eggs. 
 The structure of the adult Ichneumon Fly varies according to 
 the kind of insect in which the early stages are spent. The 
 difference is most marked in the length of the egg-laying 
 apparatus or ovipositor. There are some species in which this 
 has been carried to an extreme degree, where it is necessary 
 to reach caterpillars in such places as their burrows in the 
 interior of a tree; in other species (Plate I., Fig. 9) it is of 
 medium length and stout for piercing through cocoons and 
 into the chrysalid contained therein. Parasites such as these 
 never see the hidden victim that is to contain their egg, but v 
 nevertheless, are marvellously acute in " sensing " all about it, 
 detecting at once its age, position, and whether it already 
 contains an egg from another individual. Parasites of cater- 
 pillars met with in the open, and directly upon which the insect 
 settles to lay its egg, naturally have quite short ovipositors 
 (Plate I., Fig. 6). 
 
 Ichneumons, which are parasites of the eggs of other insects, 
 are, of course, very small, the tiny egg serving as a cocoon. 
 It is not uncommon for a small Ichneumon to emerge from 
 every egg in a batch of the Vapourer Moth. It was once thought 
 that every insect had its Ichneumon parasite attached to it 
 and that the Ichneumon confined itself to that one species,. 
 but now quite long lists of different victims are accredited to 
 single species of Ichneumon Flies. This does not mean that 
 any Ichneumon parasitises any other sort of insect it comes 
 across far from it. The parasite's life-history is very closely 
 bound up with that of its victim, and it is only such insects 
 as will so accord with its own life-history and its own peculiar 
 
structure that it will prey upon. It apparently never makes, 
 a mistake, but how it knows amongst the diverse insects met 
 with which are suitable to it and which are not is still somewhat 
 of a mystery. 
 
 TACfflNID FLIES. 
 
 Though Tachinid Flies (Plate I., Fig. 5) do immense good 
 in destroying caterpillars, it would be serving no useful purpose 
 to deal with them fully with a view to preventing their destruc- 
 tion, for they can only be recognised by the expert entomologist. 
 Superficially, they are much like the common House-Fly, an 
 appearance which is also shared by several other flies which are 
 troublesome pests. Many species of Tachinid Flies are larger 
 than the House-Fly. A close examination of all would show them 
 to be covered with strong bristles. Their habits are akin to 
 those of the Ichneumon Flies , but the egg or eggs are deposited 
 either upon the skin of the grub they attack or upon its food 
 plant. The resulting maggots eat their way into the interior 
 of the creature and feed there, or possibly in certain cases the 
 Tachinid eggs may be eaten by the grub with its food, and 
 reach its body in that way. The grubs feed within the bodies 
 of their hosts. On becoming full-fed they eat their way out 
 and form a puparia, very much like those of the House-Fly, 
 and on emerging from them the flies again deposit their eggs. 
 
 These insects are true flies, not like the Ichneumons, which 
 are related to the bees. They possess but two wings, and the 
 mouth is formed for sucking. 
 
 HOVER FLIES. 
 
 Syrphid Flies, or Hover Flies as they are also called, belong 
 to the true flies, though many present a somewhat close super- 
 ficial likeness to certain bees and wasps. They, nevertheless, 
 have but two wings and sucking mouths, the main character- 
 istics of their whole Order. The Syrphid group is a large one 
 which comprises some pests (e.g.., the Narcissus Flies), many 
 kinds which are neutral, and a number which are beneficial to 
 a high degree. 
 
 The grubs of the latter, together with the Ladybird and 
 the Lacewing, comprise a trio of voracious devourers of Aphides 
 or Greenfly, and are frequently found in company. There is 
 little danger of the very active-winged adult falh'ng a victim 
 to the destroying hand or foot, though undoubtedly the mis- 
 guided zeal of the gardener only too often finds vent against 
 his good friend in the grub or maggot stage. 
 
 Description and Life-History. The Egg of the Syrphid Fly 
 is cylindrical and pale yellow in colour. It is deposited amongst 
 Aphides on the stem or leaf of a plant. 
 
 The Grub (Plate II., Fig. 2) is an unprepossessing-looking 
 maggot, dirty-white or greenish in colour, more pointed at the 
 
liead end and without legs. It is to be seen moving about with 
 a,n undulating motion on roses, cabbages, and most other plants 
 infested by Aphides. On meeting with one, it seizes it with its 
 mouth, having a peculiar habit of raising it in the air while 
 its juices are extracted. Any maggot resembling that shown 
 by the figure and found crawling on the surface of Aphid-infested 
 plants, is almost sure to prove a Syrphid Fly grub, and as such 
 should always be allowed to continue its way in peace. Some 
 species are marked with a diamond-shaped pattern along the 
 back, and some have a pinkish hue showing through from the 
 interior. 
 
 The Pupa (Plate II., Fig. 3). When the maggot is full-fed, 
 a semi-transparent case (Puparium) is formed on the plant, 
 from which the fly emerges in due course. 
 
 The Perfect Insect (Plate II., Fig. 1). Few can have failed to 
 observe on a sunny day numbers of black and yellow striped flies of 
 fair size hovering and darting in the air and anon settling on 
 the leaves of some plant. These are usually Hover Flies, the 
 parents of the Aphis-eating maggot. The commonest and 
 perhaps most beneficial species is figured. 
 
 LACEWING FLIES. 
 
 Lacewing Flies belong to the same class as the Dragon-Flies, 
 huve biting jaws, " feelers " or antennae, and four wings which, 
 with their many fine supporting ribs, have the appearance of 
 net or lace hence the popular name of the group. The wings, 
 which are large, are carried flat when at rest against the sides 
 of the body, extending beyond it and obscuring the whole 
 hinder portion. The most familiar members of the group are 
 beautiful green insects with golden eyes. Other species are of 
 the same form, but smaller and a plain brown in colour. 
 
 Many Lacewings, when in the grub stage, are sometimes 
 confused with Ladybird grubs, and are not inferior to them in 
 their inexhaustible appetite for Aphides. They may also attack 
 Scale Insects or other pests, and some have the remarkable 
 habit of covering themselves with small pieces of lichen, bark, 
 -&c., or even with the empty skins of their victims. All Lacewings 
 are valuable and should on no account be destroyed. 
 
 Description and Life-History. The Eggs (Plate II., Fig. 5) 
 are easily recognisable, being laid in groups of fifty or less on 
 leaves, &c., and are attached by long, hair-like stalks or pedicles. 
 This peculiar stalk attachment is of value, as the young grub is 
 so extremely voracious that, were not the remainder of the 
 batch of eggs out of reach, it would, on hatching, certainly 
 devour them, together with any other grubs that were emerging. 
 
 The Grub or Larva (Plate II., Fig. 6) is sometimes supposed 
 to resemble that of the Ladybird, but is dark-brown, more 
 pointed towards the " head " end, while the large sharp mandibles 
 -or jaws are a prominent feature. 
 
6. ^aazwt/na aAA>a.s(7.)(Liipa 
 
The Pupa. When the grub is full-fed it spins a cocoon 
 (Plate II., Fig. 7), composed of semi-transparent silk, usually 
 in some crevice or cranny or down a hollow stem. Inside the 
 cocoon it turns to a pupa. 
 
 The Perfect Insect or Imago (Plate II., Fig. 4). The 
 illustration shows one of the brilliant green Lacewings which 
 may be found alike in town and country, and is probably 
 familiar to most. Its delicate appearance and beautiful 
 coloration will readily distinguish it from all other insects 
 likely to be met with. Those in search of it should look 
 specially in the neighbourhood of buds covered with Greenfly, 
 and it may often be seen flying rather slowly at sundown ; later 
 it sometimes comes to lights in houses. 
 
 ARTIFICIAL ENCOURAGEMENT OF BENEFICIAL INSECTS. 
 
 Five kinds of insects extremely beneficial to the farmer, 
 gardener and fruit-grower in fact, to all whose activities take 
 them amongst plants for their cultivation have been touched 
 upon. The five taken do not exhaust the list but are chosen as 
 being by far the most important. 
 
 Apart from the obvious duty of avoiding their destruction 
 whenever possible, the question naturally arises as to whether 
 beneficial insects can be increased or encouraged artificially. In 
 this connection there are two distinct possibilities : (1) the 
 introduction of new kinds of parasitic insects into countries in 
 which they do not already exist ; (2) the increase by artificial 
 means of parasites already established in a country. With 
 regard to the first possibility, it has been clearly demonstrated 
 that where a foreign pest has been introduced into a country 
 without its parasites, then great good may result if such parasites 
 are brought in and released. Thus, if England is so unfortunate 
 as to be colonised by a foreign insect, one of the methods of 
 defence will be to make sure that all the invader's parasites and 
 diseases are introduced as well. An instance in which this 
 method of pest control has proved a great success is that of the 
 destructive Australian Scale Insect (Icerya purchasi, Mask.), which 
 has spread from Australia to other countries. It is difficult to 
 control by artificial means, but is kept down completely by its 
 natural enemy, a Ladybird (Vedalia cardinalis, Muls.), which is 
 now introduced to any country in which the Scale Insect obtains a 
 foothold. In the same way Ichneumons have been introduced 
 into America and other countries to combat foreign insect 
 enemies which have already established themselves. 
 
 Under these conditions, artificial encouragement of parasites 
 is a proved success, but the case is far otherwise when attempts 
 are made to increase artificially the numbers of a parasite 
 already plentiful. It cannot be said that attempts to this end 
 have been generally successful, and it is only under special 
 circumstances that even hopeful results can be claimed. The 
 
10 
 
 most usual condition for success and no case exists in Britain- 
 is where there are great climatic differences between different 
 parts of a country. Thus, in certain parts of the U.S.A., Lady- 
 birds migrate to the mountains in the autumn and spend the 
 winter in large colonies, only working down to the low ground 
 again when warmed by the spring weather. Naturally the warm 
 weather first reaches the valleys while the mountains are still 
 cold and thus pests, which have spent the winter in the valley, 
 get a start and can breed for a time free from their Ladybird 
 enemies. By collecting the Ladybirds from the hills, where they 
 occur together in millions, they can be brought to the valleys 
 and sold by the pound ! They are then released as soon as the 
 pests begin to appear in spring. 
 
 A second case in which artificial assistance can be given to the 
 control of pests by parasites is where it is necessary to collect by 
 hand large numbers of the pest. The best instance of this is 
 shown by the Apple Blossom Weevil* (Anthonomus pomorum, L.), 
 which causes " capped blossom," and is one of England's most 
 serious apple pests. If the capped blossoms are collected 
 before the beetles have emerged, many of the blossoms will 
 contain, not weevils, but an Ichneumon parasite (Pimpla 
 pomorum, Ratz.) which has killed the weevil. In the case of one 
 Cambridge orchard, Immsf has shown that as many as 26 per 
 cent, of the destroyed blossoms contained Ichneumons-. Now, if 
 instead of burning the collected blossoms, they are placed in a 
 muslin cage, the Ichneumons can all be released and the weevils 
 killed, with the result that far more parasites should be available 
 next year to kill a smaller number of pests. This method of 
 dealing with Blossom Weevil has never been tried in England, 
 but in France, in one case at all events, success is claimed. 
 
 Yet another condition favourable to the encouragement of 
 parasites is sometimes found when pest and parasites leave their 
 pupae at different seasons. In the case of the Gout Fly, for 
 instance, it appears that whereas the fly comes out about harvest 
 time, the parasites remain within their pupae in the barley, 
 which are threshed out in the drum and appear in the 
 " cavings." If the latter are burned, the parasites only are 
 destroyed, while, if left, they will come out later and assist in 
 controlling the fly. 
 
 Lastly, conditions for success may be found in the case of 
 plants grown under glass. If a really destructive parasite of any 
 of the more serious glass-house pests such as the White Fly 
 can be discovered it would pay to keep a stock going to 
 distribute when needed in any infested house. The discovery 
 of the parasite in this case is of course the first step. 
 
 These cases are all mentioned to show that while it is 
 necessary to be sharply on the look-out for any means of 
 
 * See Leaflet No. 15, to be obtained from the Ministry and also- 
 included in Sectional Volume No. 2, price Wd., post free, 
 t (Annals of Applied Biology, Vol. IV., p. 211). 
 
11 
 
 encouraging parasites, yet, in Britain at all events, the chances 
 are not very many. We can be thankful for the help already 
 given by them, which is inestimable, but we cannot yet manage 
 that they shall do all the work, and artificial control measures 
 are therefore needed. 
 
 Nevertheless recognition of Beneficial Insects should be wide- 
 spread -and their destruction avoided wherever possible, for all 
 alike ultimately share the benefits they confer. Without 
 Beneficial Insects cultivation would be impossible. 
 
 TECHNICAL DESCRIPTION OF PLATES. 
 
 PLATE I. 
 
 Pig. 
 
 1 Adalia bipunctata, Linn. (Coleoptera, Coccinellidae). 
 
 2 Ova of do. do. 
 
 3 Larva of do. do. 
 
 4 Pupa of do. do. 
 
 5 Compsilura (Phorocera) concinnata, Mg. (Diptera, Tachi- 
 
 nidaa). 
 
 6 Ophion luteus, Linn. (Hymenoptera, Ichneumonidae). 
 
 7 Apanteles glomeratus, Linn. (Hymenoptera, Braconidae). 
 7a Cocoons of do. do. 
 
 8 Blastoihrix sericea, Dalm. (Hymenoptera, Chalcididae). 
 
 9 Pimpla instigator, Fab. (Hymenoptera, Ichneumonidae) 
 
 PLATE II. 
 Kg. 
 
 1 Syrphus balteatus, De G. (Diptera, Syrphidae). 
 
 2 Larva of do. do. 
 
 3 Cocoon of do. do. 
 
 4 Chrysopa vulgaris, Schn. (Neuroptera, Chrysopidae). 
 
 5 Eggs of do. do. 
 -6 Larva of do. do. 
 7 Pupa of do. do. 
 
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PUBLICATIONS ISSUED BY THE IMPERIAL 
 BUREAU OF ENTOMOLOGY. 
 
 THE BULLETIN 
 OF ENTOMOLOGICAL RESEARCH 
 
 (PUBLISHED QUARTERLY) 
 
 Containing original articles on Economic Entomology 
 (illustrated). Annual Subscription in advance fop 
 Vol. xiii (1922), 15s. post free; separate parts 5s. each, 
 post free. 
 
 PRICES OF BACK PARTS ON APPLICATION 
 
 THE 
 
 REVIEW of APPLIED ENTOMOLOGY 
 
 (PUBLISHED MONTHLY) 
 
 Containing reviews of current works on Economic 
 Entomology throughout the world. Published in 
 two Series, " A " dealing with insect pests of cultivated 
 plants, and "B" dealing with insects conveying 
 disease or otherwise injurious to man and animals. 
 Annual Subscription in advance for Vol. x (1922), 
 Series "A" 12e.; Series "B" 6s., post free. 
 
 PRICES OP BACK PARTS ON APPLICATION 
 
 A separate Subject Index to Series " A," Vols. i-iii, 
 is also published. 
 
 ROYAL 8VO., 332 pp. 5s. NET, POST FREE. 
 
 AN ABSTRACT OF THE LEGISLATION 
 
 in force in the BRITISH EMPIRE, dealing with 
 
 PLANT PESTS and DISEASES up to the year 1920. 
 
 ROYAL 8yo., 65 pp. 2s. Gd. NET, POST FREE. 
 
 Orders should be sent direct to THE ASSISTANT DIRECTOR, 
 
 THE IMPERIAL BUREAU OF ENTOMOLOGY, 
 
 41, Queen's Gate, London, S.W.7. 
 
MINISTRY OF AGRICULTURE. 
 
 COLLECTED LEAFLETS. 
 
 The Ministry has decided to replace the series of Bound 
 Volumes of 100 consecutive leaflets by attractive Sectional 
 Volumes on distinct subjects. 
 
 The Sectional Volumes are published in stiff grey paper 
 covers and will be sold at prices between Qd. and 1*. 6dL, according 
 to cost of production. 
 
 No. 1. Fungus Pests of Fruit Trees. (Price Sd, t post free.) 
 This volume contains all the Ministry's leaflets on Fruit Fungus 
 Pests, revised to date and illustrated by some 20 plates, together 
 with an introduction by the Ministry's Mycologist. 
 
 The description of the fungi, the causes leading to the attack, 
 the susceptibility of varieties, and the measures of control, are 
 given in the case of each disease. 
 
 No. 2. Insect Pests of Fruit Trees. (Price I0d., post free.) 
 The volume on Insect Pests of Fruit Trees contains about 
 100 pages of text, revised to date, including an introduction by 
 the Ministry's Entomologist, and is well illustrated. 
 
 The subjects are divided into sub-sections : " Plants Attacked 
 and Nature of Damage," " Description and Life History," and 
 " Measures of Control." 
 
 OTHER VOLUMES. 
 
 No. 3. Cultivation and Diseases of Potatoes. (Price Sd., post 
 free.) 
 
 No. 4.- Fruit: Its Cultivation, Marketing and Preservation. 
 
 (Price Is. 6d., post free.) 
 
 No. 5. Diseases of Animals. (Price is., post free.) 
 
 Order direct from the Ministry, 10, Whitehall Place, 
 London, S.W.I. 
 
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