The Caddis Flies, or Trichoptera, of Illinois

Abstract

The caddis flies, or Trichoptera, are for the most part medium-sized to small insects resembling moths in general appearance. Their larvae are aquatic in habit and caterpillar-like in appearance. The order Trichoptera contains over 750 species, ranking about seventh among the insect orders. For Illinois, we have now recorded 184 species, the largest known list for any state. It must be remembered, however, that Illinois does not have the same wealth of diverse aquatic situations as some other states, the lists of which will be greatly increased with intensive collecting. In 1931, when this project was started, the only available listing of Illinois species was contained in Dr. Cornelius Betten's then unpublished manuscript of the Trichoptera of New York. In this. Dr. Betten listed not only published records but also the results of his own collecting in the vicinity of Lake Forest, Illinois. This list enumerated 37 species for Illinois. Since that time we have added 146 species to the list, showing how poorly the caddis fly fauna of the entire midwestern and central states was then known.