Page:Popular Science Monthly Volume 70.djvu/63

From Wikisource
Jump to: navigation, search
This page has been proofread, but needs to be validated.

Tabular Summary of the Development of Insects in the Various Geological Periods

PSM V70 D063 Summary of insect development in various geological periods.png

The signs denote that, compared with the same group as now existing, a group falling in a given period was relatively more abundant, smaller, or equally developed, respectively, in the next younger period.