The entomology collection of the California Academy of Sciences is one of the four largest entomology collections in the continental United States. It contains about 14,000,000 curated specimens, representing all orders, nearly all families, and approximately 250,000 species of insects, myriapods, and arachnids. In addition, there are approximately 3 million partially processed specimens from Madagascar and 4.5 million worldwide specimens in the unprocessed backlog.
Taxonomic strengths of the collection reflect the past and present research interests of the curators, including Coleoptera (beetles), Embiidina (web spinners), Diptera (flies), Hymenoptera (ants, bees and wasps), Neuropterida (lacewings and antlions), Mecoptera (scorpion-flies), and Arachnida (spiders, scorpions and allies). Geographic strengths of the collection include western North America, Baja California, the Galápagos Islands, western South America, the Philippines, the Indo-Australian region, continental Africa, and most recently Madagascar.