The present enumeration of the TABANIDAE known to occur in Trinidad is based almost entirely on specimens seen by myself, although I have included the very few published records apparently based on reliable identifications. None of the material was collected by me; but I am indebted for it to various museums and private collectors: Dr. J. G. Myers, Mr. D. Vesey-FitzGerald, Dr. Neal Weber, Mr. John Smart and Mr. H. Oldroyd (British Museum), Mr. L. L. Pechuman (Cornell University), and Dr. Alan Stone (U.S. Bureau of Entomology and Plant Quarantine).

1. An examination has been made of all specimens labelled Leucoptera daricella (Meyr.), standing in the collections of the British Museum and of the late E. Meyrick.

2. Crobylophora staterias, Meyr., and Crobylophora onychotis, Meyr., two species previously regarded as synonymous with Leucoptera daricella, are thought to be good species. The specimens of the former, which were bred from Plumbago, have been received from India and Ceylon ; the latter is an Indian species.

3. A new African species, Leucoptera caffeina, Washbn., is described, which causes damage to coffee trees.

4. Records of Leucoptera daricella have been investigated, and, as a result, the writer is of the opinion that this species has not yet been recorded outside Australia, and that records from Africa, India and Burma, prove unsubstantiated.

5. Lectotypes are cited of the species Leucoptera daricella (Meyr.), Crobylophora staterias, Meyr., Crobylophora onychotis, Meyr., and these are in the British Museum (Natural History), London.

Representatives of three species of sawfiies attacking guava (Psidium guajava, L.)in Brazil, were recently sent for determination by Dr. Louis Pyenson, formerly head of the Entomology Section of the Instituta de Pesquisas Agronomicas, Pernambuco, Brazil.

The adults of the Gregarious Guava Sawfly are relatively sluggish insects and can be readily captured on foliage (Pyenson 1938 b). They lay their eggs in single rows embedded in the tissue of the tips of young green twigs or along the midribs on the underside of the younger leaves.

The grape vine (Vitis vinifera), which is a common fruit crop grown extensively in Mysore, has not been noticed till now to be subject to any very serious insect pests, though one occasionally comes across a Chrysomelid beetle (Scelodonta strigicoUis, Mot.), stray leaf-eating cockchafers (Adoretus spp.), twig-girdling Longicorn beetles (Sthenias grisator, F.), and stray scale-insects, which, however, have not done any very serious damage so far ; but recently substantial damage has been caused to the grape vine crop by an insect which appears to be quite a new record—at any rate for S. India. The insect concerned is a species of plume moth (Oxyptilus regulus, Meyr.), the larva of which bores into the ripening berries of the grape bunches and causes substantial injury. The grapes grown in the Mysore State belong to a local black variety, the fruits of which have a sub-acid taste and do not therefore fetch good prices at present because of the very large imports of sweet varieties from North India and elsewhere. The serious nature of the damage done by this new pest and the consequent menace to the grape crop, which is one of the oldest of the fruit plants to be raised in the State, and the likelihood of the insect extending its activities to the different varieties of this crop cultivated outside the State, prompted the author to attempt a fairly thorough study of the insect with a view to adopting control measures.

As cotton crops in many parts of the world end either with the onset of winter or of the dry season, it is natural that the larval diapause which becomes more and more conspicuous as the crop ripens should have come to be regarded as an instance of either hibernation or aestivation; yet in the West Indies where the following observations were made, there is no winter, nor does the ripe boll phase of the crop necessarily fall in the dry season. The latter moreover is not one of complete drought but rather dry only by comparison. Indeed in some islands, such as Montserrat and St. Kitts, the crop is harvested in the wet season. Yet long-cycle or resting larvae are regularly found in all of these islands.

The following is an account of the continuation of experiments and observations carried out in connexion with an investigation into the ecology and control of pine beetles, with special reference to Myelophilus piniperda and M. minor.

The object of the present paper is to describe the results of some cage experiments with Zonocerus variegatus, L., carried out at Ibadan between March 1932 and December 1937.

The cages used for the breeding experiments were about 2-05 metres in height and were filled with soil to a depth of about 51 cm. The upper part of each cage was made of wire gauze and had a cubic capacity of about 1-43 cubic metres (154 cm. high by 102 cm. by 91 cm.). The grasshoppers were fed on the leaves of sweet cassava (Manihot utiHssima) and water was sprinkled on the food.

The wheat crops in certain districts of England are attacked every year by the wheat-stem sawfly, which in its turn acts as host to various species of parasitic insects. The aim of the present investigation is to try to discover from an analysis of records if any sort of simple numerical relations exist within the complex including the wheat field, the sawflies which infest the wheat-stalks, and the parasites which attack the sawflies. The results of this work lead to a discussion of the peculiar difficulties involved in the application of mathematics to the study of animals and plants in their natural environments.