Exploring the NCBI taxonomy database using Entrez Direct

I’ve been meaning to write about Entrez Direct, henceforth called edirect, for some time. This tweet provided me with an excuse:

OK tweeps, I'm looking for estimates of species richness in insects. Any orders, families, or genera with good estimates you know of? pls RT

— Robert Lanfear (@RobLanfear) April 1, 2015

This post is not strictly the answer to that question. Instead we’ll ask: which parent IDs of records for insects in the NCBI Taxonomy database have the most species IDs?