Prior to the arrival of E.W. Baker in 1944, the acarological holdings of the U.S. National Collection were composed of a range of material, mostly unidentified, acquired through donations from the professional entomologists who preceded him. Baker can be credited with helping to consolidate and organize these disparate collections into a world-class reference collection. Material contributed by E.A. McGregor focused primarily on plant-feeding mites of North America and was collected from 1912 to 1965. H.E. Ewing amassed a substantial collection of mites from the family Trombiculidae (chiggers) during his career, and he began donating material even before he was appointed to the USDA in 1919. Other major early contributions include:

Water Mites-

Newell Collection: ~2,000 vials, ~1,300 jars, and ~108,100 slides

Parasitic Mites-

Yunker Collection: ~6,000 vials, ~12,900 slides

Plant-Feeding Mites-

Keifer Collection (Eriophyidae) : ~450 vials, ~80 boxes of dry material, ~16,400 slides

Baker Collection: ~10,600 slides

Soil Mites-

Jacot Collection: ~4,200 slides

Bee Mites-

Delfinado Collection: ~6,200 slides

Miscellaneous-

Bartsch Collection: ~65 vials, ~20 type slides

Hull Collection: ~1,800 slides

Lukoschus Collection: ~500

Metz and Farrier Collection: ~1,900 slides

Rettenmeyer Collection: ~550 slides

Smiley Collection: ~21,400 slides

The most recent inventory of the U.S. National Mite Collection found 1,0754 alcohol samples, 450 dry samples, and more than 332,000 slides housed at the Systematic Entomology Laboratory, Henry A. Wallace Agricultural Research Center, in Beltsville, MD. Additional material is under the supervision of collaborating institutions.

Tick Collection

This collection was acquired by F.C. Bishopp and was later combined with the collection of the Rocky Mountain Laboratory of the National Institutes of Health, Hamilton, MO. These collections are currently curated by L.A. Durden and J.E. Kierans at the Institute of Arthropodology and Parasitology, Georgia Southern University.

Chigger Collection

The Trombiculidae collection is presently held by M.L. Goff at the Department of Entomology, University of Hawaii at Manoa.

Phytoseiidae Collection

The predator mites of the family of Phytoseiidae have been studied extensively by H.A. Denmark. Currently, curation of this collection is supervised by W.C. Welbourn at the Florida Department of Agriculture, Division of Plant Industry, Gainesville, FL.

The maintenance of the U.S. National Mite Collection is an on-going concern, and is currently overseen by Ronald Ochoa. Important new additions to the collection are being obtained from A. Fain, L'Institut Royal des Sciences Naturelles, Brussels; B. OConnor, University of Michigan Museum of Zoology, Ann Arbor; S. Mahunka, Hungarian Natural History Museum, Budapest; J.C. Moser, USDA Forest Service, Pineville, LA.