Illinois is one of the very few states that maintain a large research insect collection. This collection is under the care and guidance of the Section of Faunistic Surveys and Insect Identification of the Illinois Natural History Survey. It is housed in the west part of the fireproof Natural Resources Building on the University of Illinois campus at Urbana, fig. 78. Begun about 1880, the collection has grown steadily until now it is the most extensive representative collection of the insect fauna of any state in the nation. The collection consists of over 5,500,000 specimens of insects housed in steel cabinets, fig. 79. The pinned collection includes about 750,000 specimens in trays. The collection preserved in alcohol contains over 3,500,000 insects including not only a great number of valuable adult insects but also a very useful collection of immature insects. The slide collection contains nearly 250,000 specimens mounted as permanent microscopic preparations. The papered and boxed material comprises more than 1,000,000 specimens of dried insects.

The most important use of the collection is for identification of insects known to damage crops, stored grains, and household articles, or to threaten human health. Important also is its use as a storehouse of information regarding the ecology, host relationships, and distribution of Illinois insects.

So large is the field of insect classification that many important gaps exist in our knowledge of the Illinois fauna. For maximum usefulness, the collection should contain a complete representation of the Illinois insect fauna, supplemented with as much additional North American material as can be obtained. This additional comparison material is frequently necessary to evaluate correctly the species occurring in the state. It is estimated that there are about 20,000 different species of insects in Illinois and 150,000 in North America. The collection contains representatives of over 15,000 Illinois species, and a great many other North American species useful as comparison material in the identification of Illinois forms.

Gifts to the collection of well-prepared material are greatly appreciated. Many of those already received have made vital contributions to the collection and added valuable records to the Natural History Survey files of insect distribution.