Brenthia pavonacella (Fig. 1) is the sole representative of the genus in North America. In Illinois, it undergoes at least two generations, with larvae occurring from early July through early September. The larva is a leaf skeletonizer on woodland-inhabiting species of trefoil, Desmodium spp. (Fabaceae), feeding on the underside of the leaflet. In its early instars, the larva causes damage that somewhat resembles "hopper burn" (i.e., the piercing-sucking feeding damage of some leafhoppers, Hemiptera: Cicadellidae), but by the time it reaches larval maturity, B. pavonacella removes large patches of leaf area, so that only the leaf veins remain intact in the area of feeding. The larva of B. pavonacella has the unusual habit of cutting a small "escape portal" hole completely through the host leaf (as do, analogously, Idioglossa and Stathmopoda, but larvae of those groups construct a silken tube that runs through the hole into a silken shelter on the upperside of the leaf, whereas Brenthia does not). In the event that the Brenthia larva is disturbed, it is very adept at quickly disappearing through this escape portal, to the opposite side of the leaf.
Figure 1. Brenthia pavonacella. Adult; leaf skeletonization (larval feeding damage) on trefoil, Desmodium sp. (Fabaceae) (fully-grown larva present on left-hand leaflet); and cocoon (from which the adult has already emerged; the pupal exuvium can be seen protruding from the lower end of the cocoon).