Idioglossa was placed in Batrachedridae by Sugisima and Arita (2000), Trans. Lepid. Soc. Japan 51: 319-336, based on the key in Hodges (1999), Handbuch der Zoologie IV/35: 131-158. Morphological structure, especially of the genitalia, convincingly argues for this placement.

We have one Nearctic species, I. miraculosa, shown here (somewhat out of focus, but I hope showing adequately the general appearance of the moth). The larva is a leaf skeletonizer on deer-tongue grass, Dicanthelium (formerly Panicum) clandestinum (Poaceae). Larvae can be abundant in central Illinois in mid- to late August. A full account of the life history of this moth can be perused at microleps.org.

The adult in this image is a reared individual that was collected as a pupa in its silken pupal tube on the hostplant, three miles east of Charleston, Illinois, 18 August, 2007. The adult was photographed in the rearing cup shortly after it emerged, four days after being collected. The adult of I. miraculosa always sits in this characteristic position, with the wings partly spread to show the dark line in the fringes as a shallow "W" figure, which meets the abdomen exactly at the point of its abrupt color change. Also shown is the distinctive antennal position, which also is seen in the related genus Stathmopoda. The prolegs are extended forward, as are the long maxillary scale tufts (unique to this genus) on which the generic name (which means, roughly, "odd tongue") is based. This is our only narrow-winged microlep that features metallic fasciae on the hindwings, and it is one of our relatively very few predominantly yellow small microleps. All in all, this is a very distinctive-looking little moth that is quite unlikely to be mistaken for anything else. I do not have or know of any hypothesis as to what might be the selective advantage to adult Idioglossa of presenting this particular appearance, but it must work, because Asian members of this genus are extremely similar in coloration to I. miraculosa, and they display exactly this same resting posture.