The NMNH Collection of Aphidoidea is the largest collection of aphidoids in North America, and one of the largest in the world. The collection is located in Room 015, Building 005, BARC-West, Beltsville, Maryland.

The collection contains in excess of 85,000 slides representing in excess of 2,300 species. It is strong in species collected in quarantine, and specimens are mostly from the USA, Europe, and Asia. The aphid collection (as opposed to Aphidoidea as a whole) contains type material for 628 species, 268 holotypes and 28 lectotypes. The associated library includes 200 volumes and 34 linear feet of reprints. The SEL staff includes Gary Miller.

The collection was built principally through the efforts of A. C. Baker, T. Pergandé, A. L. Quaintance, and L. M. Russell. They contain types and identified specimens described and studied by A. C. Baker, A. Fitch, F. C. Hottes, P. W. Mason, J. O. Pepper, T. Pergandé, A. L. Quaintance, C. V. Riley, A. G. Robinson, L. M. Russell, M. B. Stoetzel, L. G. Strom, and A. N. Tissot.

The collection is housed in rectangular 5-drawer boxes, each of which has three columns for slides. Each slide is kept inside a plastic or paper sleeve. This storage method is compact, effectively keeps loose labels together with their slides, and has advantages for expansion of the collection. Most of the slides are balsam mounts, with a few slides using other mountants such as euparal, polyvinyl alchohol, and Hoyer's medium. Nearly all the material added to the collection prior to Miss Russell's time as curator was mounted without clearing. For many species in the collection this uncleared material constitutes the bulk of the holdings.

Material in the collection has come from several major sources. Valuable donations were made by F. C. Hottes, J. O. Pepper, A. G. Robinson, L. G. Strom, and a few others, and the various curators of the collection have added their own collections. But by far the most important source of specimens for the collection has been the aphids submitted from all around the world for identification. Many of these are collected in plant quarantine operations of USDA-APHIS. Many specialists around the world have deposited paratypes in the collection, adding to its value tremendously.