As editor of this volume I am not going to emphasize the economic importance of the Bruchids of pulses, nor how necessary it is to know the conditions of infestation of crops in order to achieve an efficient protection; both points are testified by F.A.O.'s sponsorship, as well as of the International Organization for Biological Control. On the other hand I would like to stress the scientific interest of the study of 'domestic' bruchids. It raises questions which require that present basic entomological knowledge be extended. I am not going to review all questions raised but I will emphasize those I am most aware of. Some bruchid species have been able to colonize habitats differing totally; some differing in their latitude, and thus their basic periodicities; others differing in their degree of complexity (sks of seeds): What are the respective roles played by polymorphism and plasticity in that exceptional capacity? What differences are there between the populations living on wild plants in dispersal areas and those living in sks? What are the alterations brought about by the drastic selection pressures in populations having later colonized habitats ecologically similar to the original habitats? What factors determine the degree of specificity of trophic relationships, and the possibilities of extension of the niche? What influences are exerted by the other elements of the original bio­ cenoses upon the behavioural evolution of these species? Such are a few fundamental problems that can be tackled directly through