Contents

16 July 1993
Vol 261, Issue 5119

About The Cover

Spindle diversity diagram for Heteroptera (true bugs) from 250 million years ago to the present, representing 39 families at its widest extent; a typical heteropteran adult (stink bug) is depicted at the top. Data from the fossil record indicate that modern insect diversity results from low extinction rates rather than high origination rates. See page 310. Insets: early Oligocene insects—from Baltic amber, a scuttle fly (left) and an ant (bottom), and from the Florissant beds, a March fly (right). [Illustration: Finnegan Marsh]