For our insect of the week for March 10, 2025, we turn our attention to one of the more bizarre insects found in central Illinois – the Ripiphoridae. I originally identified this specimen as a member of the order Strepsiptera. R. J. Millena recently pointed out my error (he is an expert on Strepsiptera). The specimen in this stacked photograph was collected by our former member, Gordon Adams, in August, 1973 (Peoria Co.). Ok, Mark – what is it? As best I can tell, this is Ripiphorus fasciatus, described by Thomas Say in 1823. Keep in mind this genus is in need of serious revision.As I understand, what we call Ripiphorus fasciatus is in fact a group of related species. If someone reading this post is an expert on the group, I welcome more insights. The common name for this group is wedge-shaped beetles. The genus is recognized by having very short elytra.

There are roughly 50 species in 6 genera in North America. It is thought that members of this genus parasitize bees in the bee family Halictidae. Eggs are likely laid on or near flowers. Larvae then attach themselves to visiting bees and are taken to the nest where they feed on the bee larva (either as internal parasitoid or external). They may also consume the food left for the bee larva as they grow and consume the entire larva. Adults do not live long.

If you are looking for a most unusual central Illinois insect, I think this one fits the bill. Yes, they are very tiny. This one is glued to a tiny point of paper.