While investigating the biological control of certain Hepialids, a very interesting Ichneumonid parasite, Alomya debellator (F.) was reared from the pupae of the Swift Moth, Hepialus lupulinus (L.).

The systematic position of this parasite has been thoroughly investigated and the members of the special sub-family, Metopiinae, to which it has been assigned, are characterised by the possession of only one trochanter on each foreleg. A. debellator is the sole representative of the tribe Alomyini.

After extensive collecting, and a thorough search of the literature, the conclusion has been reached that the distribution of this parasite is fairly local, but its range in Great Britain and certain other European countries is wide. As a result of the present study H. lupulinus has been definitely proved to be the host of A. debellator.

A fairly full account of the life-history of the parasite has been worked out, and amongst other things, a point of special interest is the arrest in development which occurs in the first-instar larva. Possible explanations of this phenomenon are discussed.

The morphological and anatomical structure of the larva have been fully investigated and described, and useful diagnostic characteristics both for the primary and mature larval stages, have been discovered.

The paper concludes with a discussion on the potential value of A. debellator as a factor in the control of H. lupulinus, and other allied species belonging to the genus Oncopera in Australia. It is maintained, on the evidence collected, that this parasite in some areas is probably the most important single factor of biological control. A note on the feeding habits of Hepialids, and a few remarks about the collecting of parasitised material are appended. Altogether some 7,000 specimens of H. lupulinus larvae and pupae many of which were parasitised by A. debellator were collected from the Willingham area of Cambridgeshire.

A detailed account of the biology and development of an important parasite of cockroaches, the Evaniid, Evania appendigaster (L.), is given. Adult and immature stages of the parasite were obtained and studied from collections of oöthecae of Periplaneta americana (L.) made in Saudi Arabia, some 25–29 per cent, of which were parasitised. There are at least three or four generations a year, a rate of multiplication which gives the parasite a very decided advantage over its much slower-breeding host (P. americana takes at least a year or more to pass through one generation).

The Evaniids are a neglected group of parasitic Hymenoptera and so far very little has been published about them.

Adult parasites emerged from the material collected in Saudi Arabia in or about February, May and October. Oviposition in this species is carried out in a rather peculiar manner. The female lies on her side and, with legs braced against the oötheca, penetrates the tough integument of the egg-capsule after about half-an-hour's hard labour. Only one egg (hymenopteriform type) is laid in an oötheca, and the larva which develops from it is solitary in habit, and completely devours all the eggs in the egg-capsule of its host. The number of larval instars was determined by an examination of the cast skins in the residual material of parasitised oöthecae, a task rendered easier by the very distinctive mandibles of the various stages. Altogether there are five separate larval instars, the first easily identified by the serried arrangement of small denticles on the mandibles. The mandibles of the next two stages are tridentate and shaped like a gauntlet glove, while those of the last two instars are sub-triangular and bidentate. The mature larva is described in detail, and recognition characters for eggs, larval instars and adults are provided.

An appraisement of the value of the two important parasites, Tetrastichus hagenowii (Ratz.) and E. appendigaster, in the biological control of cockroaches is made. It is pointed out that T. hagenowii in certain areas destroys from 15–57 per cent, of the eggs of its host and E. appendigaster 25–29 per cent. Both the former, with up to six generations a year, and the latter, with three or more, multiply much more rapidly than their host. Between them the two parasites appear to be capable of destroying up to 50 per cent, of the cockroach population.

The host records and general distribution of five species of Evania, one each of the related genera Prosevania, Zeuxevania and Brachygaster, and two of Hyptia, all of which parasitise the oöthecae of cockroaches, are fully documented. E. appendigaster itself has been recorded from the main species of cockroach, P. americana, P. australasiae (F.), Blatta orientalis L., Cutilia soror (Brunner) and Neostylopyga rhombifolia (Stoll), and its distribution ranges from Europe (Hungary) and the Middle East (Palestine) to the Pacific (Hawaii and Fiji), America (Gulf and Atlantic States), and the West Indies (Jamaica).

In this paper the cockroach, a general name used here to include the commoner species of Periplaneta, Blatta and Blattella, etc., is approached from an economic and medical point of view. Special emphasis is placed on the possibilities of its control by biological methods, and to this end the whole field of its inter-relationships with other organisms in various parts of the world has been carefully surveyed. As a result some 73 parasites, predators and symbionts from such widely diverse groups as the Protozoa, Nematoda, Insecta, Arachnida, the Algae and Bacteria have been reviewed and classified.

The more important parasites, some 25 in number, have been placed along with the chief predators in a group (A) by themselves. Most of the former are members of the Hymenoptera-Parasitica, the more prominent being the Eulophid, Tetrastichus hagenowii (Ratz.), and the Evaniid, Evania appendigaster L., with six of its congeners. Amongst the predators of this group, certain Sphecoid wasps of the genus Ampulex, represented by seven distinct species, take pride of place. In the second big division (B) the individual species are mostly members of the Protozoa, with Endamoeba as a prominent genus, and of the Nematoda, with several genera, most of them in the Oxyuroidea.

The present paper, which is intended to serve as the introductory one of a series on the natural enemies of the cockroach, deals in detail with a very important parasite, namely the Eulophid, Tetrastichus hagenowii.

1. The moth—Cydia nigricana—whose larvae bore into the pods of developing peas and render most of the contained seeds unfit for human consumption is considered by some authorities to be one of the principal insect pests of agriculture in Canada. It is particularly destructive in the Maritime Provinces and British Columbia, while in Ontario it increased to such proportions that the farmers of that province had to give up growing mid-season peas altogether.

2. This state of affairs is attributed to the fact that the pea moth was accidentally introduced from Europe in 1893 without the insect parasites which attack and check it in its native home. At any rate no parasites have emerged from the representative collections of pea moth material made by the Canadian entomologists in the affected areas, while three species with a combined parasitism of up to 60 per cent. have been reared by the writer from cocoons of the moth in England. Furthermore, in Canada, where parasites of this particular pest are absent, 10–50 per cent. of the pea crop and sometimes as much as 75 per cent. or more, is said to be destroyed annually by the moth larvae, whereas in England, where they are present, the attack is usually comparatively slight.

3. The paper opens with a general account of the biology of the pea moth including systematic descriptions of the adult and developmental stages, and notes on the host-plants and distribution of the insect.

A paper by the present writer on an Ichneumonid parasite of Hepialus lupulinus (L.) under the name Alomya debellator (F.) appeared in the last issue of this journal (1950). It now transpires that this Ichneumonid is not A. debellator but Ichneumon suspiciosus Wesm. This error was pointed out, as soon as the paper was published, by Mr. J. F. Perkins of the British Museum, and agreed by Mr. G. J. Kerrich of the Commonwealth Institute of Entomology, both of whom, as specialists in the Ichneumonidae, recognised the illustration produced from a drawing prepared by Mr. A. J. E. Terzi as representing a species of Ichneumon, probably I. suspiciosus. The actual specimen illustrated has been traced, and its identification has been confirmed by Mr. Perkins as Ichneumon suspiciosus Wesm. It is certain, moreover, that all the parasite material involved was this species and not A. debellator.

1. In Canada, European holly (Ilex aquifolium) can only be grown successfully in the mild, humid climate of western British Columbia. The sales of cut holly for decorative purposes amount to several hundred thousand dollars annually, and the tree is also in good demand for ornamental planting in public parks and private estates.

2. The most serious pest of holly in this part of the world is the Agromyzid fly, Phytomyza ilicis, or the Holly Leaf-miner, which was accidentally introduced from Europe without its attendant natural enemies. The larvae of this insect produce large unsightly blotches on the leaves which greatly lower the value of the cut foliage. As a rule 75 to 80 per cent. of the leaves are attacked in this manner.

3. Since chemical forms of restraint offered little hope of success, it was decided that the biological method of control should be given a trial. Accordingly, the writer undertook a general survey of the fly and its parasites in England, the results of which are described in the preceding pages. An account of the biological control of P. ilicis will be published in a separate paper at a later date.

4. A general account of the systematics, synonymy, distribution, host relationship, and biology of the holly fly itself precedes the parasite section.

1. While investigating the parasites of the holly leaf-miner (Phytomyza ilicis Curt.) with a view to utilizing them in the control of this troublesome pest of holly in western Canada, a species of Opius, which on examination proved to be new to science, was reared from the fly puparia.

2. A fairly complete account of the general systematics, distribution, biology, and morphology of the various developmental stages of this parasite is set down in the preceding pages. The primary larva is particularly interesting because of its unusual orientation. After the anatomical details had been worked out it was discovered that the concave side of the larva, which would normally be regarded as the ventral surface, is actually the dorsal one.

3. The genus Opius, whose distribution is world-wide, contains a very large number of species which parasitize important economic pests. In temperate regions the insects which suffer most from their attacks are species of Pegomyia, Agromyza, Rhagoletis, Phytomyza and Cerodonta, whilst in tropical and subtropical areas the most favoured hosts belong to one or other of the two genera Dacus and Anastrepha.

4. The host relationship of the genus, because of its importance from both economic and taxonomic standpoints, is discussed at some length.

5. In the first stadium Opius ilicis is a larval parasite, but the three succeeding instars live in the host pupa, and the imago emerges from the puparium. A very interesting phase in the life history of this parasite occurs towards the end of the first stage. At this point the development of the larva is arrested and further growth cannot take place until the host has pupated.

6. Very little work has so far been carried out on the larval morphology of the Opiinae, but that done up to the present, including the foregoing descriptions, would seem to indicate that the larvae of this tribe form a fairly homogeneous group. The main distinguishing characters of these larvae are listed in section VII of this paper.

7. It is pointed out that O. ilicis, in spite of being intrinsically inferior to Chrysocharis gemma, is responsible for the destruction of a certain number of hosts which escape the attentions of the latter parasite, and although the percentage accounted for is small (maximum parasitism in 1939 4%), it nevertheless fills a particular niche of its own, and so must be of some definite value in the scheme of control.

8. The chief method employed by the first instar of Chrysocharis gemma in the destruction of rival Opius larvae would appear to be direct mandibular attack. Several reasons have been put forward to account for the decided inferiority which is exhibited by the Braconid when it comes into conflict with this Chalcid.

9. In section X, a number of interesting points which have a general bearing on the study of parasite larvae are discussed. These include the cephalic skeleton and its probable function in successive instars, the taxonomic value of this structure in the parasitic Hymenoptera, the apparent absence of a tracheal system in the second and third instar larvae of O. ilicis, and arrested development in the Opiinae and some related forms.

This paper has two objectives. The first is to explore the creation of a Highland policy area in the 1880s. Emphasis will be placed on the use of historical arguments by the government in the course of the construction of the Crofters Holdings (Scotland) Act of 1886, especially in the attempt to justify confining the operation of that statute to the Highlands. The second theme, explored in the latter parts of the paper, concerns the strategies which succeeding governments have used to justify the perpetuation of a distinct Highland policy area. An element of continuity in Highland history in the twentieth century has been the special treatment of the area by governments. On the occasions when this has caused resentment in other rural areas of Britain, the Scottish Office response has been to argue that the Highlands are a special case because of the existence of the crofting counties with their special code of legislation. Clearly, this is a tautological argument and it is hoped that this paper, by exploring the period from the creation of the crofting legislation in the 1880s, to the late twentieth century, will shed some light on its origins. It will be argued that this has created a climate of fear in the Highlands and particularly the crofting community, but also, on occasion in the Lowlands. Further, there are occasions when the existence of a special Highland policy area has served to marginalise Highland policy. The paper falls into five main sections: the first will briefly review the literature about the Highland/Lowland division in Scotland, the second will look at the origins of the Crofters' Act of 1886, the third will examine the period from 1906 to 1911 when aspects of crofting legislation were extended to the rest of Scotland; the fourth section will identify the inter war period as an era when Highland policy became more diverse and the final section will scrutinise the impact of that more diverse approach in the years after the Second World War.

If a rural historian who has few credentials to undertake the current review may begin this essay with a point from his own field of research: there is a view of Scottish rural history which argues that far too much attention has been paid to the Highlands. A similar view could be advanced about concentration on Glasgow in Scottish urban history; in addition to the volumes under consideration have been numerous other recent titles. As Professor Morris has noted in a recent review article in this journal, however, other Scottish cities, especially Aberdeen and Dundee, have recently been subjected to variants of the ‘urban biography’ approach. Aberdeen, in particular, has come under intense scrutiny with a two-volume history sponsored by the local authority and taking advantage of the rich resources of the city archives. Edinburgh, by contrast, and notwithstanding the recent culmination of Professor Rodger's extensive researches, remains the poor relation of Scottish urban history: aside from the classic account of the creation of the New Town by A.J. Youngson and the late R.Q. Gray's account of nineteenth-century social history, the existing historiography of Scotland's capital city remains interred in the pages of unpublished theses and scholarly journals.

I have been deeply moved by your invitation to deliver this year's Maudsley Lecture. Founded to commemorate so distinguished a man, it has become most properly one of the honours of psychiatry.

Studies of the effects of the repetition of statements, i.e., verbal signals, upon the behaviour of chronic psychoneurotic patients have been carried out in the Allan Memorial Institute continuously since 1953 (1).