Identification
Adult Markings: The forewing has a whitish-gray ground color with darker grayish-brown to brownish-black markings. The most prominent mark is a sub-basal transverse band that extends from the middle of the wing to the inner margin at an oblique angle. A smaller and less oblique pretornal band or blotch is usually present at about four-fifths near the inner margin. Just anterior to this, there is often an irregular, and often oval-shaped, blotch near the middle of the wing. The costal margin has a well-defined series of dark bars and lighter strigulae. The hindwing is pale grayish brown with a dark band along the marginal scales (Grehan et al. 1995; Gilligan et al. 2008). Catastega aceriella resembles C. timidella and a few other olethreutine moths, and is best assigned to genus using genitalia. Brown (1986) noted that our two Catastega species can usually be identified based on wing patterning. The sub-basal transverse band on C. aceriella typically extends from the middle of the wing to the inner margin, while the band terminates before reaching the inner margin in C. timidella . The latter species also has more extensive dark blotching on the costal half of the wing that produces a weakly two-toned appearance (Brown 1986, Gilligan et al. 2008). Both of our Catastega species produce distinctive tubular frass cases on the undersides of leaves and have different hosts that allow reliable identifications to species. Many of our locality records for both species are based on larval records.
Wingspan: 12-17 mm (Heinrich, 1923; Grehan et al. 1995).
Adult Structural Features: The following is based on Brown's (1986) general description of the genitalia of Catastega . In males, the uncus is bifid and the socii broad, setose, and ventrally fused with the bases of the gnathos. The anellus does not closely surround the base of the aedeagus and is often cuplike. The valva has a saccular spine cluster, while the cucullus is poorly defined or delimited by a deep ventral invagination. In females, the lamella postvaginalis is reduced. The lamella antevaginalis is developed and forms a conelike sterigma around the ostium. The ductus bursae has a sclerotized band posterior to the inception of the ductus seminalis. There are two signa present. The male anellus and female sterigma are apomorphic for Catastega and helpful in distinguishing them from species that are similar in external maculation (e.g., certain Gretchena ). C. timidella and C. aceriella cannot be separated easily by characters of male genitalia. However, female C. aceriella are distinctive in that sternum VII lacks rugae, tergum VIII and the papillae anales are narrower, and the sterigma is more rounded than in C. timidella . The author provides illustrations of the female genitalia of both species.
Genitalia and other structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The pale yellowish-green larva binds together an expanding leaf to make a tent, then spins a thin sheet of webbing on the underside of the leaf to create a feeding chamber. The feeding chamber is often constructed near the base of an expanding maple leaf between two of the primary veins. As the larva feeds, it constructs a distinctive funnel-like structure for protection that is woven from fecal pellets and silk. The size of the protective fecal funnel is slowly expanded as the larva window-feeds on the leaf surface, and the chamber can be straight or broadly curved. Larvae typically retreat into the funnel when they are not actively feeding. The leaf becomes progressively buckled with age and may eventually become partially folded. The final instar eventually leaves the shelter and moves to the ground where it constructs a cocoon between two leaves. Overwintering occurs in the pupal stage, and the adults emerge the following spring or early summer (Cote and Allen, 1973; Rose and Linquist, 1997).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
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