01 July 1994
Vol 265, Issue 5168

About The Cover

An eyespot (2 mm across) on a Precis coenia (buckeye) butterfly wing. The size, color, and number of eyespots and other patterns are determined in the developing wing imaginal disc (a field of undifferentiated cells in the caterpillar) several days before the adult pattern appears. Genes involved in insect wing formation are expressed in various patterns in butterflies to create detailed patterns within the butterfly wings. See page 109 and the Perspective on page 44. [Photo: Steve Paddock]