"Lyonetiidae" in the 1983 checklist included the tineoid/gracillarioid-allied groups Bedelliidae, which is covered on this page, and Bucculatricidae, and also the yponomeutoid family Lyonetiidae (as defined on basis of the genus Lyonetia).
Bedelliidae contains one genus, Bedellia, two species of which are known from North America. Bedellia somnulentella (Fig. 1) occurs in Illinois. The larva is greenish with a dark red spot on either side of each segment; it presents a sigmoid ("S"-shaped) configuration, in contrast to most other leaf-mining microlepidoptera larvae, which either appear straight or describe a single, gentle curve from anterior to posterior end. The larva of B. somnulentella makes a full-depth blotch mine on morning glory, Ipomoea sp. (Convolvulaceae); usually, several larvae feed per leaf. The appearance of a typically-infested leaf, with numerous feeding "windows" and a small accumulation of stringy black frass just outside each mine, is distinctive.
The larva sits with the anterior part of the body inside the leaf mine, the posterior part outside the mine, and with a persistent accumulation of frass protruding from the posterior opening of the digestive tract. It is possible that this retention of frass serves a defensive purpose, as it is at least superficially reminiscent of the "shield defense" behavior that is seen in some chrysomelid beetle larvae, e.g., Blepharida rhois on sumac, Rhus sp. (Anacardiaceae) (Vencl and Morton 1998).
In central Illinois, the larva matures in mid- to late August. The larva leaves the mine to pupate, with the pupa being suspended in a slight silken hammock. The pupal exuvium is protruded from the cocoon upon eclosion. Adult emergence occurs straightaway, in early September; this suggests that the moth overwinters in the adult stage.
The adult of B. somnulentella is a pale grayish-brown moth, the forewing of which is uniformly speckled with dark-brown scales except on the dorsal margin from base to tornus, the latter area being whitish. The moth sits with the front end of the body elevated, as in Tischeriidae and gracillariine Gracillaridae but with the front and hind legs tucked out of sight and the middle legs visible but not projected to either side. On the head, there is a prominent tuft of erect scales.
Figure 1. Bedellia somnulentella. Adult, and leaf mines on morning glory, Ipomoea sp. (Convolvulaceae). In the central panel, three larvae can be seen in their leaf mines. In the right-hand panel, a larva sits in typical habitus.