The coevolution of insects and fleshy fungi has received little attention in North America. In contrast, the European insect associates of fleshy fungi have been extensively surveyed(...). However, even these studies have only begun to reveal the nature of the relationship between fungal hosts and their mycophagous insect inhabitants. The purpose of the present investigation was to survey the insect associates of the Boletales in the upper Midwest and to examine the characteristics of bolete fruitbodies that affect their utilization by mycophagous insects. Members of 16 families of flies and 3 families of beetles were reared from fruitbodies of the Boletales in this study. The diversity of insects found is comparable to that reported from European fleshy fungi, and many species of both insects and hosts in the Midwest are identical with those reported from Europe, while in other cases congeneric insect species occupy similar niches to their European counter parts. It is clear both from the known biology of these insects and from their observed host-age preferences that not all fungivores feed at the same trophic level. Some feed initially on fresh fungal tissue, but many others feed principally on decaying hosts. The latter group of insects contains many occasional associates or polyphagous fungivores with no particular preference for the boletes. The bolets also attract many specialist insect associates, and, compared to most other fleshy fungi, the number of specialist fungivores is exceptional.