Eriocraniella falcata Davis 1978

Eriocraniella (Disfurcula) falcata

Dyseriocrania species Opler, 1974:4

ADULT (Figure 173).—Wing Expanse: , 7–10 mm; , 7–10 mm.

Head: Relatively sparsely covered with white to cream white hairs. Antennae moderately long, 0.55–0.6 the length of forewing, 40–45 segmented; scape mostly cream white, slightly irrorated with fuscous ventrally; flagellum almost entirely fuscous except for dorsal suffusion of white over basal 5–6 segments and for slender white scales over apical 5–7 segments. Maxillary palpi brownish fuscous, frequently suffused heavily with silvery white ventrally; apex of terminal segment with a single, relatively large apical lobe bearing one large, bluntly rounded seta and 3 smaller, more acute setae of variable lengths, and 2 pair of smaller subapical lobes, each bearing a single, elongate acute seta apically; all setae with striated sides. Base of galeae mostly naked, sometimes with scattered, narrow whitish scales. Labial palpi brownish fuscous above, silvery white ventrally.

Thorax: Dorsum uniformly light bronzy brown; tegulae with an elongate tuft of cream white hairs. Venter mostly silvery white. Legs cream white to stramineous except for dorsum of tibial and tarsal segments of forelegs. Forewings uniformly bronzy brown, often with a pale golden luster; fringe brownish at base, becoming paler and whiter toward outer edge; Sc usually divided, crossvein r present. Hind wings slightly darker than forewings, less iridescent but with a slight purplish luster, becoming darker toward outer margins; scales relatively broad, particularly over outer half; crossveins m and m-cu present.

Abdomen (Figures 239–240): Sparsely covered with slender bronzy brown, hairlike scales above, whitish ventrally. Fourth sternite of female with a pair of relatively small, nearly circular fenestrae approximately 0.3 the length of sternite in diameter; male without fenestrae. Sternal tubercules present on 5th sternite of both sexes, papiliform, diameter approximately 0.17–0.22 the length of sternite. Caudal apex of 8th sternite sharply defined in female, normally bifurcate, though occasionally merely concave; apex of 8th tergite deeply divided.

Male Genitalia (Figures 273–274): Uncus deeply bilobed; lobes prominent, lateral margins straight but tapering; lobes widely separated at apex for a distance equivalent to their length. Anal tube membranous, without basal sclerites. Vinculum with median caudal margin not raised, relatively truncate; median cephalic margin between apophyses smoothly concave, not extended, apophyses elongate, approximately 0.73–0.77 the length of undivided vinculum. Juxta broadest immediately anterior to middle; lateral margins nearly parallel; greatest width approximately 0.45–0.6 its length; caudal apex subtruncate to slightly rounded (convex). Base of aedeagus moderately swollen; ventral phallic branch relatively stout, approximately equal in diameter and length to dorsal branch; apex of ventral branch acute, with a small spinose process loosely articulated subapically; length of subapical process varying from 0.5–1.2 the diameter of ventral phallic branch; remainder of ventral branch without lobes or processes.

Female Genitalia (Figures 323–325, 341): Apex of ovipositor acuminate; lateral edges serrulate, with 5–7 minute teeth. Bursa copulatrix of moderate length, slightly surpassing cephalic apices of posterior apophyses when extended; walls of corpus bursae entirely membranous. Bases of anterior apophyses symmetrical, not unusually swollen. Vaginal sclerite darkly sclerotized, relatively narrow and elongate with greatest width only 0.24–0.27 its length; a prominent, falcate ventral keel present along midline, with apex projecting caudally as shown in Figure 325.

HOLOTYPE.—, Cloudburst Canyon, San Gabriel Mts, T2N, R12W, Sec 14, 4000 ft [1220 m], Los Angeles County, California, 10 May, 1972, J. P. and K. E. Donahue; in the Los Angeles County Museum.

PARATYPES.—UNITED STATES. CALIFORNIA: Los Angeles Co: Big Tujunga Canyon, 3300 ft [1006 m] on Angeles Crest Hwy: 1 , 1 , 11 May 1973, R. H. Leuschner (RHL). Cloudburst Canyon, San Gabriel Mts, T2N, R12W, Sec 14, 4000 ft [1220 m]: 1 , 2 , 30 Apr–10 May 1972, J. P. and K. E. Donahue (LACM). Josephine Cr, San Gabriel Mts, T2N, R12W, Sec 6, 3350 ft [1021 m]: 7 , 14 , 9 May 1973, J. P. and K. E. Donahue, genitalia slide DRD 2998, genitalia slide DRD 2999 (LACM); 1 , 1 , 9 May 1973, J. P. and K. E. Donahue, genitalia slide USNM 18184, genitalia slide USNM 18189 (USNM); 1 , 11 May 1974 D. C. Frack (DCF); 9 , 1 , 18 May 1973, D. C. Frack (DCF); 1 , 18 May 1973, D. C. Frack (USNM). Josephine Cr, 3300 ft [1006 m] on Angeles Crest Hwy: 12 , 2 , 11 May 1973, R. H. Leuschner (RHL); 3500 ft [1067 m]; 1 , 11 May 1973, R. H. Leuschner, genitalia slide DRD 3003 (RHL). Mt. Wilson Rd, 4600 ft [1402 m] on Angeles Crest Hwy: 1 , 11 May 1973, R. H. Leuschner, genitalia slide USNM 18159 (USNM). Littlerock: 1 , 28 Mar 1964, P. Opler, genitalia slide DRD 2901 (UCB). 3000 ft [915 m] on Angeles Crest Hwy: 5 , 2 , 11 May 1973, R. H. Leuschner (RHL); 1 , 2 , 11 May 1973, R. H. Leuschner, genitalia slide USNM 18186, genitalia slide USNM 18188 (USNM). San Luis Obispo Co: San Luis Obispo: 1 , March, A. Vachell, genitalia slide USNM 18205 (USNM). Santa Clara Co: Herbert Cr, 3 mi [4.8 km] W New Almaden: 2 , 28 Apr 1969, P. Opler, Quercus chrysolepis, genitalia slides PAO 87, DRD 2957 (UCB); 1 , 28 Apr 1969, P. Opler, Quercus chrysolepis, slides USNM 16102, 18194 (USNM); 1 , 18 Apr 1969, J. Powell, flying under Q. agrifolia 12:00 noon, genitalia slide DRD 2975 (UCB). Described from a total of 43 males and 30 females.

HOST.—Fagaceae: “Quercus chrysolepis Liebm.,” Opler (1974) and from specimen labels.

FLIGHT PERIOD.—Late March to mid-May; univoltine.

DISTRIBUTION (Map 5).—This species occurs through the Coast Ranges of Central California from Santa Clara County south to the San Gabriel Mountains of Los Angeles County, where it is found at elevations up to 1400 m.

Eriocraniella falcata is a moth of the family Eriocraniidae. It was described by Davis in 1978. It is found in the Coast Ranges of central California.

The wingspan is 7–10 mm for both males and females. The forewings are uniformly bronzy brown, often with a pale golden luster. The hindwings are slightly darker than the forewings and less iridescent, but with a slight purplish luster, becoming darker toward the outer margins. The scales are relatively broad, particularly over the outer half. Adults are on wing from late March to mid May in one generation per year.

The larvae feed on Quercus chrysolepis. They mine the leaves of their host plant. The early instar linear mine is unusually long. The mine continues to the leaf margin and then abruptly enlarges to form a full depth blotch usually covering the apical third to one-fifth of the leaf.