The description of insect coloration has long been an attractive field for naturalists and systematist , s.of the chemical nature of pigments and the associated literature has in creased considerably (39,40,154). In 1959, Cromartie (29) reviewed data about the chemical nature of coloring substances of insects. The aim of .this review is to survey the recent discoveries covering approximately the 'iast ten years, in the more important pigment families and biological subjects.Both epidermal and cuticular levels of pigmentation will be considered. With respect to cuticular pigmentation, the problem of knowing whether darkening and hardening \Vere identical remained unresolved. To under stand the present knowledge of it well, it is necessary to review work con cerning the general chemical production of the cuticle during the molting process and to consider recent progress about the nature of dark pigment itself.These descriptions must be followed by a discussion of some problems of metabolic interrelations between pigments. Despite the progress, it often re mains difficult to establish a relationship between the chemical description of pigments and the visible coloration of insects; a special discussion will deal with this problem.Physiological color changes concerned with the site of colored granules within the cell are often reviewed and very few new data are available; they are not included in this paper. On the other hand, morphological changes by synthesis of new pigments constitute a large field in which there is great activity: homochromy, gregarization, changes under light influence or related with diapause. The entire subject of color polymorphism requires detailed analysis. RECENT PROGRESS IN THE KNOWLEDGE OF PIGMENT NATURE Ommochromes.-Two important groups of pigments derived from tryp tophan, ommatins, and ommins, were chemically identified (29, 94) and their distribution in the animal world well reviewed by Linzen (94). In the light of these studies it is possible to summarize the situation. Ommatins are represented by (a) xanthommatin, the simplest basic pigment formed by 403 6033 Annu. Rev. Entomol. 1972.17:403-424. Downloaded from www.annualreviews.org by University of Miami on 09/17/13. For personal use only.Quick links to online content Further ANNUAL REVIEWS