We are indebted to the Toronto Engraving Company, Limited, for the beautiful plate given in this month's issue. The invention of the trichromatic photographic process of illustration is undoubtedly one of the most important stimuli to scientific work of recent years. Especially is this the case in the study of insects, where it is frequently necessary to depict accurately very slight differences, both in form and colour, which could be described only with difficulty, or at greath length.