No description available.

No description available.

No description available.

The interest of the problem lies in the fact that Sitophilus zea-mais Motschulsky and Sitophilus oryzae (Linnaeus) are so closely related that they have only recently been separated as two distinct species. A third species Sitophilus Eranarius (Linnaeus) commonly found with them in the same habitats was also used in these experiments. A comparative study of the behaviour of the three species was carried out. The different behavioural aspects examined in the present work were the preference of the weevils for oviposition sites , some factors inducing flight, their climbing ability on glass, their reactions in different humidity gradients and in a temperature gradient, and finally their behaviour to a source of light. The behaviour of the fourth instar larvae in a horizontal beam of light and in a steep humidity gradient was also determined. The sensory organs involved in some of these mechanisms were located and described. The differences in the behaviour pattern of the three species substantiate their taxonomic separation.

Taxonomy of the family Alydidae has been in confusion in the past. Some of the recent authors (e.g. China and Miller, 1959) have not accepted its family rank and its lower categories have been virtually ignored. During the present studies the abdomen and its appendages (the genitalia) of the various representatives of the family Alydidae have been examined to evaluate their importance in the classification of higher and lower categories. Prior to this revision the subfamily Leptocorisinae Stal (Div. Leptocorisaria of the subfamily Alydina) contained eight genera and thirty eight species including major rice pests of the Far East. There was confusion over the identities of many species and since Stal (1873) no world wide revisional work had been undertaken and in his work only fourteen species (including some synonyms) ware covered. During the present studies three new tribes, one new genus, two new subgenera, twenty one new species have been described and one species, on account of its homonymy, has been renamed. Stenocoris Burmeister (1839) (subgenus sensu Stal, 1873) has been given generic rank and has been separated from Leptocorisa Latreille 1829, an application has been made to the International Commission on Zoological Nomenclature to supress Leptocorixa. Rhabdocoris Kolenati 1845 (subgenus of Leptocorisa Latreille sensu Stk, 1873) has been synonymised with Leptocorisa. The undescribed misidentified type species of the subgenus Erbula has been renamed and described and a request has been made to the International Commission on Zoological Nomenclature to use its plennary powers to retain the subgeneric concept unchanged (see Appendix 2). Nine previously described species have been considered synonyms, whilst four of the species regarded as synonyms by earlier workers have been reinstated. Three of Bergroth's genera, formerly included in the Leptocorisinae have been transferred to the tribes of the subfamily Coreinae (sensu Stal 1873). They have been redescribed and figured and two new species described from within them.

Detailed histological studies of the brains of 23 species of Lepidoptora reveal a remarkable uniformity in the disposition, multiplicity of neurosecretery cells, and in the number of most types of cells. The recognition of A-, B-, C- and D-calls is based upon tho paraldehyde fuchsin staining technique. These maajor categories are further divided, to give a total of 10 types of cells. In all species neuresecretery cells are confined to medial and lateral groups of the pars intercerebralis. with the exception of medial B-cells, all of the neurosocretery cells that occur in the adult become differentiated during the second larval instar. The cycles of secretion and increases in volume of the cytoplasm are estimated in 6 types Of cells and correlated with physiological processes. In adults, activity Of the neurosecretory cells was studied in the short-living saturniid moth, Philosamia cynthia ricini, and compared with the comparatively long-living noctuid, Trip-haena pronuba. Circadian cycles of secretion in the medial Al-and A2-cells are correlated with diuresis and flight activity respectively. A detailed histochemical analysis provides evidence in support of the assumption that inclusions in the various types of neuresecretery cells differ in chemical composition. It is suggested that the inclusions of A- and C-cells are glyoproteins and that the B-cell inclusions are proteins. There is histochemical evidence that A2-cells also contain 5-hydroxytryptamine. Factors affecting activity were analysed, using an actograph designed to record the insects in flight. An endogenous flight rhythm was demonstrated in nocturnal moths. Thu effect of ablating neuresocretery cells and areas of the brain was studied, and a hypothesis of hormonal control of flight activity is put forward. The role of 5-hydroxytryptamine in the initiation and maintenance of the circation flight rhythm is discussed.

The study of the family Ceraphronidaein the British Isles confirmed the desirability of raising this family to the status of a superfamily. This thesis gives keys to separate the families of Ceraphronoidea, and the subfamilies and genera of these families. In the subfamily Megaspilidae of the family Megaspilinae, the genus Conostigmus is treated in greater detail and a key to the British species is given. This genus is here divided into two subgenera, Conostigmus and Consulcus (subgenus new). Twenty-eight species are redescribed with figures to facilitate recognition, and twelve new species are described and figured. One new genus Scuto-cervix is erected for a single species previously described in Conostigmus. The genus Megaspilus is redescribed with figures. Among the types studied in the British Museum, seven have been placed as new synonyms. In the course of the study several European species not represented in the British Isles were examined. Several new characters for identifying genera and species have bean discovered; greater attention being given to use of sculpture and comparative measurements than previously.

No description available.

No description available.

The swede midge Contarinia nasturtii (Kieffer), a member of the family Cecidomyidae (Order, Diptera), is a small insect, the larvae of which induce gall formation on numerous cruciferous plants. Kieffer (1888) first described the midge which he reared from larvae occupying the closed flowers of Nasturtium palustre D. C., now known to be Rorippa islandica (Oeder) Borbas. In subsequent years numerous authors have reported the midge, under various synonyms, as a frequent pest of several important cruciferous crops. Briefly this thesis re-examines the life-cycle of the swede midge in detail and investigates the effect of what seem to be the important environmental factors on successive stages of development. After consideration of the observed population fluctuations of C. nasturtii at Nafferton, Northumberland, during 1957-1960, the thesis concludes with a discussion of population change in relation to various components of the environment.